78 



THE PRACTICAL ENTOMOLOGIST. 



tebrate animals wc may trace an anologywith the above 

 four stages as follows: — 1st, the foetus in the womb; 2ud, 

 the baby feeding upon milk and without food at first; >ird, 

 the child feeding upon solid food and furnished with, teeth; 

 4th, the adult man or woman, distinguished from the 

 child by well known sexual characters and capable of 

 propagating the species. The chief difference in the two 

 cases is, that in Insects the change from one state to ano- 

 ther' takes place suddenly by a sudden moulting of the 

 skin, or rather v/hat is properly speaking the external 

 skeleton, whereas in vertebrate animals it takes place 

 slowly and gradually. For example, we can fix no pre- 

 cise day, and even no precise mouth, and scarcely any 

 precise year, when the Baby becomes a Boy, or when the 

 Boy becomes a Man, while it often takes but a few mi- 

 nutes for a Chrysalis (pupa) to change into a Butteriiy, 

 or a Caterpillar i larva) to change into a Chrysalis, and we 

 may watch the whole process with the greatest ease, from 

 beginning to end, by devoting an hour's attention to it. 



In a very few species of Insects, such as the common 

 Walking Stick or Prairie Alligator {Diapheromera femo- 

 raia)'^ the perfect insect never has any wings at all; and 

 in a few others, such as the common Bed-bug and the 

 Flea, the Perfect Insect has only rudimental wings, or 

 short stumps of wings, such as we usually see in the Pupa. 

 But even here we may distinguish the diflerout stages by 

 the successive moultings, and we may know that the 

 insect has arrived at the perfect state by its copulating. 

 It is a universal rule that larvfe and pupre never copulate, 

 for the same reason that calves and lambs never copulate, 

 i. e. because they are as yet in an immature state. 



You will find the Natural History of the Chinch Bug 

 well explained by Mr. Riley in an article in No. 6 of the 

 Practical Entomologist (pp. 47 — S.) The only point in 

 ■which I differ from him is, that I believe that there are 

 more than two broods of thein every year, and probably 

 as many as four or five in this latitude. 



C. Cook, Mass. — The small cocoons you send from off 

 the twigs of aiiple-trees contain a black pupa from which 

 I have bred several specimens of a very minute moth, 

 apparently undescribed. I am about to forward Ae to Dr. 

 Clemens, who has made these small mollis his special 

 study, and who will probably name and describe it. All 

 the specimens sent seem to belong to the same species. 



From the mass of cocoons found attached to the egg of 

 the Tent Caterpillar of the Apple-tree, which you former- 

 ly sent, I have bred several specimens of the very same 

 species of Microgaster which we told you it was likely to 

 produce, and also several specimens of another small Ich- 

 neumon-lly belonging to the genus Jlemiieles. The ques- 

 tion .till remains to be solved, whether the larvae of both 

 these Ichneumon-flies lived as co-tenants in the body of 

 their victim, the Caterpillar, and spun the mass of cocoons 

 in common, or whether — which I decidedly incline to be- 

 lieve — one of them is parasitic upon the other, and if so 

 which is parasitic upon which. From the fact that the 

 Memitcles came out several weeks before the Microguster, I 

 rather infer that the latter is parasitic upon the former. 

 Please next year send me additional specimens, so as to 

 solve tills curious question. 



Wm. Manlius Smith, N. Y.— You are quite right aa to 

 the cocoons o( Sclundria rihis (Winchcll) not being mere 

 "balls of earth," as was wrongly stated in the Practical 

 E.N-TOMOLOoisT, No. .S, p. 23, but trut! silken cocoons. From 

 the specimens you sent I have bred four specimens of the 

 insect, which were a welcome novelty to my cabinet, and 

 from which I perceive that Prof. Winchcll was mistaken 

 in referring the insect to the genus Sclamh-ia. It belongs 

 to Nemalus, having only one marginal cell, and therefore 

 its true name \sXematus ribia. The female is very remark- 

 able for having 10-jointed antennae, while the male has the 

 number of joints, viz. nine, that characterize the genus. 



A very similar species of iS'cma<«« infests the Gooseberry 

 and Currant in Europe, and it is perhaps the case that our 

 American insect is the same species imported among us 

 from the other side of the Atlantic. (See on the European 

 species Westwood's Introduction, II. pp. 103—4.) 



Charles Dadant, Illinois. — The eggs you send found in 

 little slits in the bark of Pear-tree twigs are those of Chlo- 

 roncura ma/efica (Walsh), a small green insect belonging 

 to the Tcftir/onia family in the Order Homoptera. I pub- 

 lished a deseriiition and figures of this insect in the 

 I'iaricFurmcriiK'\A. G, 1802, and of its egg-slits /4id. April 



•Figured Ilarris Jnj. Ins., p. 147. 



4, 1863, p. 212, together with some account of its habits. 

 The former article was reproduced in ih& Proceedings of 

 the Boston Society of Natural History, 1864, pp. 314—317. 



The similar egg-slits found in the bark of the Delaware 

 grape-vine appertain to some other Ilomopterous Insect, 

 probably to Proconia undata, a much larger species be- 

 longing to the Tcttigonid family, which I know to ovijiosit 

 in this manner in the grape-vine. You should have sent 

 pieces of the twig containing the egg-slits, and not merely 

 thin slices of the bark. 



Jno. Floumoy, Mo. — The insects you send, found on the 

 leaves and stems of the Chickasaw Plum, are some kind of 

 Plaint Louse {Aphis.) It is impossible to say what par- 

 ticular species they belong to, because they were simjily 

 wrapped in a piece of paper and reached me broken into a 

 hundred fragments, and pressed as flat as a pancake. A 

 naturalist might bo able to say, with some degree of cer- 

 tainty, that a sausage contained dog's-flesh,from meeting 

 with a dog's tooth iu it; but it w^ould jiuzzle even Cuvier 

 or Owen to decide* from such data whether the dog was a 

 Terrier, a Spaniel or a Pointer. 



As a general rule, almost every plant has its own par- 

 ticular species of Plant-louse: for example, that of the 

 Apple is distinct from that of the Cherry, that of the Cab- 

 bage from that of the Currant, and so forth. They all 

 live by sucking the sap of the plant they infest, and 

 although the infested leaves oftenshrivel and curl up, yet 

 it is impossible for them to be eaten bodily by this insect, 

 for the simple reason that it has gotno jaws to eat with — 

 nothing, in fact, but a long beak to suck with. Conse- 

 quently, " the stripping of the foliage" of your trees last 

 year must have been caused by some entirely distinct in- 

 sect — perhaps some kind of caterpillar. From the enor- 

 mous rapidity with which Plant-lice breed, there is no 

 doubt that if they were allowed to multiply without any 

 check, they would in a few mouths ruin almost every 

 plant on the face of the earth. But there are hundreds 

 and hundreds of different insects that prey upon thera 

 voraciously, so that it is but seldom that they do material 

 damage. I incline to believe, that in limited numbers, 

 they operate asasummerpruning.and are therefore more 

 beneficial than injurious to fruit-trees. In particular 

 years the Hop Plant-louse has greatly injured the hops, 

 and inotheryears the Grain Plant-louse in certain Stales 

 has damaged the small grain considerably, but it is re- 

 corded to have been generally checked up in the end by 

 myriads of Cannibal Insects, chiefly Lady-birds (Cocci- 

 netla). I have myself seen the Devil's Darning Needles 

 (Agrlon) flying among my Currant Bushes and pouncing 

 ferociously on the Plant-lice that swarmed on them. It 

 is a good plan, and one which has long been practised by 

 European gardeners, to collect a number of Lady-birds 

 and place them on any plants that are grievously infested 

 by Aphis. Fumigation with tobacco in a close room will. 

 kill Plant-lice on tireen-house plants, and on choice gar- 

 den plants, such as Verbenas, they may be destroyed by 

 dipping the infested branches for a few minutes into strong 

 soap-suds. 



A. C. Hammond, Illinois. — You say that some of your 

 Plum-trees arc dying from the attacks of Borers, of which 

 supposed Borers you forward three difl'erent kinds. The 

 first of these — the "white grub" — is, as you suppose, the 

 true Peach Borer, which in myarticle on Borers (No. 4, p. 

 27) was stated, on the authority of Dr. Fitch, occasionally 

 to attack the Plum-tree. Hence your observations are va- 

 luable as confirmatory evidence of the fact, and of the fur- 

 ther very remarkable fact that Plum-trees, when attacked 

 by the Peach Borer, do not exude gum like Peach-trees. 

 The second specimen — " the long, slender, brown worm " — 

 is the larvaof some kind of '• Click-beetle" {Elatcr), nnne 

 of which are true Borers, though a great matiy of them 

 live in decayed wood, and a few of them attack the roots 

 of living plants, when they are pojmlarly called "Wire- 

 worms." Most of these larvro, like the specimen sent, 

 are hard, shining, cylindrical, mahogany-colored insects, 

 looking like an inch or so of brown wire cut off nearly 

 square at each end. The third specimen — "the short, 

 dark worm " — arrived in such bad order, having been eat- 

 en up almost bodily by the Peach Borer on the road, that 

 all that I can say is that it is distinct from the other two. 



I apprehend it is the Peach Borerthat is the I'eal author 

 of the damage to your trees; and you must fight him on the 

 same principles ]n-pcisely as if you found him on a Peach- 

 tree. Most certainly the Wire-worm (or Elatcr larva) 

 would not invaded your trees, but for their already contain- 

 ing decayed matter, the handiwork of the Peach Borer. 



