THE PRACTICAL ENTOMOLOGIST. 



77 



ANSWEES TO CORRESPOE LENTS. 



BY B. D. WALSH, M. A.— Associate Ebitok. 



B. F. Scibert, N. J.— The insects you sent^oval, about 

 one-fifth of an inch loug, of a dull blue-black color, ami 

 ■with fine, long, silky hairs, especially on the thorax— are 

 the Serica tricolor of Say. They arrived all alive and lu 

 first-rate order, and you did well in sending jilenty of spe- 

 cimens. The species of this genus are numerous, and re- 

 eemble one another very closely ; and by examining'sc- 

 veral score out of the bountiful supply you lurnished, I 

 -was enabled to ascertain, that the characters by which 

 it difl'ers from some very closely allied species are per- 

 fectly unchangeable, and do not run promiscuously those 

 of one species into those of another. Although this in- , 

 Beet is said to occur generally throughout the United i 

 States, vet I never met with it near Rock Island, though | 

 I have "received it from my entomological friend, Dr. Le- 

 Baron, of Geneva. Illinois. 



You say that •' you find them very numerous as well as 

 very destructive, as they have eaten all the leaves oIF 

 your neighbor's and yourowu Pear-trees and Strawberry 

 plants ;"°and that " the moment you touch the tree, they 

 all drop to the ground." This is the first instance on re- 

 cord, so far as I om aware, of this particular species being 

 injurious in the field or the garden. According to Say, 

 " it abounds in hilly and mountainous situations, where, 

 in the month of May, it may be seen flying about among 

 the Whortle berry bushes in great profusion." Hams 

 states with regard to two other species of Serica — the ucs- 

 pertina and the sencea— that i' they attack the leaves of 

 the sweet-briar, on which they may be found in profusion 

 in the evening, about the last of June." (Inj. Ins. p. 33.) 

 A colored figure of vcspertina is given in his plate II, fig. 

 14; and if you diminish the size and add some fine, silky 

 hairs, the same figure would answer very well for our 

 species. 



These insects belong to the Order of Beetles ( Coleoptera) 

 and to the same great family {Scaraba:idce) in which arc 

 included our May-bug (or May-beetle) and our Eose-bug, 

 and also the European Cockchafer— three ruinously de- 

 structive insects. It is not known where or how the larva 

 lives, but it probably burrows under ground and feeds on 

 the roots of living vegetation. The -'dropping to the earth" 

 when the tree, on which the perfect Beetle occurs, is 

 touched, is not so common in this Family, as among the 

 Snout-beetles (Curculio Family) and the Chrysomcla fa- 

 mily, which last includes the striped cucumber-beetles 

 and several other injurious species. 



Th03. Siveter, Iowa.— .You refer to the article on "the 

 Measuring Worm (Ennomos .mbaignaria)" in No. 7 of the 

 ■Practical Entomologist, and you very justly state that 

 the account there given of its habits does not at all agree 

 with those of the Measuring Worm which infests your 

 Apple-trees. No wonder. They are two entirely distinct 

 insects. The insect that troubles you is evidently, from 

 the very correct statement you give of its Natural History, 

 the common Canker "^onxt—Anisopteryx vernata—v/Ki^h 

 is as different from Ennomos subsignaria as a sheep is from 

 a cow. Both, it is true, are Measuring Worms; but there 

 are hundreds of distinct species of Measuring Worms found 

 in the United States, each with its peculiar size, shape 

 and color, its peculiar habits and its peculiar food-plant 

 or food-plants. 



The writer of that article, like many other learned men, 

 supposed that those whom he was addressing were as 

 familiar with learned names as himself, and that, by 

 merely giving the scientific name of the insect which he 

 •was writing about, everybody would understand what 

 particular species he referred to. There are, in fact, some 

 things in that paper which I cannot understand myself, 

 for example where he talks about the half-growrt cater- 

 pillars "commencing their saltatorial exercises." "Sal- 

 tatorial" means -'jumping" or "leaping;" and if this 

 particular Measuring Worm ever jumps or leaps, it is 

 more than I ever saw any other kind of Measuring Worm 

 do, though I am familiar with scores of dilferent kinds. 

 It is possible, however, that this may be a peculiar habit 

 of this peculiar species, which, although it swarms in cer- 

 tain localities in the Eastern States, does not appear to be 

 found in the West. But I have myself bred from the cat- 

 erpillar another species of the same genus — Ennomos viag- 

 naria — which agreed with the subsignaria in spinning a 



loose cocoon of open net-work about tho end of August 

 and in coming out into the moth state tho same season, 

 viz: on Sept. •11. This cateriiillar fed upon oak, while the 

 subsignaria, if I remember right, is said to feed chiefly 

 upon elm. But it performed no --jumping" or "leaping" 

 operations whatever w hile it was in my breeding-cage. 



You will find figures of both male and female Canker 

 Worm moths in Harris's Injurious Insects, pfi. 4G1--2. 

 The other insect, which, as it swarms chiefly in cities, 

 and esDic'ally in New York, maybe called the "City 

 Span-worm, ' is not noticed in that work nor in Dr. Fitch's 

 Acw Tork leporis. The leading points of diilercnce in 

 the Natural History of the two Insects may be thus b-i( fly 

 stated: — In the Canker Worm itis themnle ni< th that 

 has wings, and they are ash-colored; in the City Span- 

 worm both sexes have wings, and they are satiny-white. 

 The Canker Worm goes under ground to pass into the pupa 

 or chrysalis slate ; the City Sjian-worm goes to ]iupa in a 

 thin gauzy cocoon which it spins among the twigs and 

 leaves'o; the tree it inhabits. The Canker Worm generally 

 lies in tho pupa state till the following spring, though a few 

 come out. in che moth st;ite late in the same autumn, and 

 on warm days during the winter; the City Span-worm 

 comes out into the moth state the same summer, and not 

 many weeks after it has gone to pupa. The Canker Worm, 

 occurs chiefly on apple and elm trees, although it is some- 

 times found on cherry, plum, basswood, &c.; the City Span- 

 worm, unless my memory fails me, is said to be found 

 chiefly on the elm and only occasionally on other shade 

 trees, but never on fruit trees. Hence it is evident that 

 the two sriccics must be att;icked in very dilierent me- 

 thods; and that tarred bandages, leaden troughs filled 

 with oil and placed around the butts of infested trees, &c., 

 ic, which, when properly applied, are efl'ective remedies 

 against the Canker Worm, whose moth comes out of the 

 earth and in the female sex is wingless, wi.uld be of no 

 earthlv use against the City Span-worm, whose female 

 moth "is winged and comes out among the twigs and 

 branches of the trees it infests. 



You will oblige me, as you seem to have more Canker 

 Worms #ian you know what to do with, by sending me 

 by mail a few dozen of them, packed in any kind of small 

 box, wi'.h leaves enough to last them on their journey. 

 The inceet is not found near Eock Island, and I wish to 

 breed it myself, so as to examine into its habits. 



H. B. Howarth, Wisconsin.- The insects you send, with 

 an enquiry whether they are not "the flies which pro- 

 duce the Chinch Bug," are the Capsus oblincatus of Say, 

 otherwise named by Beauvois as Piu/tocoris linearis. You 

 will find the species figured in Harris's Injurious Insects, 

 p. 201, and another figure with an accompanying article 

 by mvself in the Prairie Farmer, May 2, IhGli. It is a 

 very common and abundant species throughout the North- 

 ern States, and, as youm;iysee from the passages referred 

 to, sometimes does a great deal of damage. Like the 

 Chinch Bug, it passes the winter in the perfect or winged 

 state, which accounts for your finding it under shocks of 

 corn in the middle of November. You notice that it has 

 "the same d.sagreeable smell as the Chinch Bug;" but 

 this it has in common with all the true Bugs (Order J/dc- 

 ropiera) which are vegetable feeders and not cannibals; 

 for examiile, tho common Squash Bug ( Coreus trists) •■•■ and 

 the B.d Bu". Not only is it a di.itinct species from the 

 Chinch Bu.g, but it belongs to a distinct genus and even 

 to a distinct Family. . 



You must disabuse yourself of the popular idea, that 

 after an Insect has arrived at the perfect state, or in other 

 words after it has obtained wings, it ever changes into 

 any other kind of Insect. Many believe that Beetles 

 change into Butterflies, Butterflies into Bugs, Bugs into 

 Bees, and so on ad ivfinilum; and I once noticed a para- 

 graph which ran the rounds of the Agrieulturul Press, 

 iravely asserting that the common Rose-bug (Macrodac- 

 tytus subspinosus] usually shed its yellow wing-cases and 

 changed into a Horse-fly {Tabaniis.) This is a mere de- 

 lusion. No Puch change can or does happen. It is as im- 

 possible as for a Cow to shed her horns and t""! '"\';^ 

 Horse. All Insects pass through four stages only, \»t the 

 e<r<r 2nd the larva, 3rd the pupa, 4th the perleet in.sect, 

 wTen in almost all species wings .are acquired, and in all 

 species the male and female pa r, the female lays her eggs, 

 and then both male and female, hnving run their ap- 

 pointed course, die. In the.human species and other ver- 



s Figured Harris's Inj. Ins., p. 194. 



