110 



THE AMERICAN ENTOMOLOGIST. 



glassy wings, and the female witli a tail-like 

 ovipositor almost as long as lier body. The 

 third is much smaller than the other two, and in- 

 stead of a single parasite attacking a single vic- 

 tim, as is the rule with those two, eight or ten 

 of them may often be found inside the almost 

 empty skin of the poor gall-making larva. This 

 last parasitic larva produces a small uniformly 

 black fly with uniformly glassy wings {Pternma- 

 lus); and what is remarkable, they lie in a little 

 bunch in the larva state inside the central cell of 

 the gall all through tlie winter, and do not 

 emerge ia the winged form until tlie following- 

 spring; whereas, the other two species make 

 their appearance in the winged state the very 

 same summer tliat the gall is generated. Be- 

 sides the above three C'/i«fciVflies, which occnr 

 in large numbers, we have also bred from the 

 Oak-apple of the Black Oak. a single small Ich- 

 neumon-^Y (Bracon), which is probably piira- 

 Z' sitic on the larva of a small moth {Gelechia yal- 

 loigenitella, Clemens) occasionally found as a 

 Guest in that as well as in two other galls. 



As to the other galls figured above, we have 

 only space to say that the Pla\it-lice of the Elm- 

 gall are extensively preyed u])oii by a 

 / small six-legged larva, with white cottony fila- 

 ments growing out of his back, which produces 

 a brown Lady-bird with a red tail (Scymjius 

 hmmorrhous, Lee.) ; and that the Plant-lice of 

 \/ the Sumac gall are, in the State of iN'ew 

 York, infested by the larva of a Syrjihus fly, 

 somewhat similar to that figured on page 83, of 

 which we have succeeded in breeding two indi- 

 viduals to the perfect fly state. For specimens 

 of these larvas we have been indebted to Dr. W. 

 M. Smith, of New York; and according to Dr. 

 Le Baron, the fly belongs to the same genus 

 {Fipiza) as that just now referred to, and is 

 also like that insect, a new and hitherto mule- 

 scribed species. 



THE BOGUS COLORADO POTATO-BUG. 



»^ {Doryphoi'a juncta, Gennar.) 



In a recent article we expressed our opinion 

 that this insect could not live upon the potato 

 vine, although it feeds naturally upon the close- 

 ly allied horse-nettle. Mr. W. Julich, of New 

 York, writes us word that at Newport News, 

 in the neighborhood of Fortress Monroe, Va., 

 he has seen thousands of this insect upon the 

 horse-nettle, but never seen a single larva upon 

 certain potato vines which grew in the imme- 

 diate neighborhood, though he had occasionally 

 observed the perfect beetle sitting upon, but 

 not feeding on, these potato vines. 



ANTS AND APHIDES. 



AVe often see it stated in tJic paiiei's tliat there is a 

 species of insect called A/jhis, tliat produoes a honey- 

 lil;e substance, whidi is fed upon by ants. 



Also, that another family of these Aphides are domes- 

 ticated bv tlie ants, tmd live with them in the ground. 



If there is any truth in these stories will you please 

 inform me tln-ong-li your paper, aud also wliether tliis 

 lioney-liko substance is the excrement, or some pecu- 

 liiu: provision of nature. Also, whether the ApTivUs tac 

 common among all species of ants. W. Batchei.ob. 



AVaverly, Pa. 



The Plant-lice belonging to certain gen- 

 era, almost invariably secrete a fiuid resemb- 

 ling honey in sweetness. It issues in limpid 

 drops not only from the end of the abdomen, 

 but from two " honey tubes ■' wlticli are placed, 

 one on each side, jnst above it. The beaks of 

 these Plant-lice are continually employed to 

 pump up the juices of the plants which they 

 attack, and these juices, after passing throngh 

 their systems, are exuded as described above, 

 and bear therefore some relation to excrement, 

 being- in fact little else but the fseces of the lice. 

 Ants are very fond of this sweet liquid, aud 

 may always be found amongst those aphides 

 which secrete it, though the latter are not neces- 

 sarily "common among all species of ants." 

 For example, it has been shown by Dr. Fitch 

 that no ants ever haunt the Grain Plant-louse 

 (Aphis acena, Fabr.), which in certain years 

 and certain districts does so much damage to 

 our crops of small grain. But although this 

 species of Plant-louse has full-sized honey- 

 tubes, it does not appear that it ever exudes 

 any honey-dew; which fully accounts for the 

 ants not visiting them. As to those species of 

 Plant-lice that, as you correctly phrase it, " are 

 domesticated by the ants and live with them in 

 the ground," they mostly belong- to a genus 

 (Pemphigus) which you will find figured on 

 page 82 (Fig. 71), and which, unlike the genus 

 Aphis, has no honey-tubes at all. Wh)', then, 

 you will ask, should the ants domesticate them, 

 seeing- that these Plant-lice secrete no honey- 

 dew? They do it for the sake of the sugary 

 matter which is exuded from the bodies of these 

 Plant-lice in the form of a whitish cottony sub- 

 stance; and we have ascertained that they often 

 bring these sugar-producing lice home to their 

 nests from the roots of certain plants, and keep 

 the sugar-producers there till after a few hours 

 a sufficient crop of the coveted daint}' has been 

 elaborated and harvested. After which they 

 carry the Plant-lice back to the roots whence the 

 due supply of sap is derived, just as a dairyman, 

 after milking- his cows, drives them back to 

 pasture to elaborate a fresh supply of milk from 

 the herbage that they find there. — Eds.] 



