124 



THE SPRING GEAIX-APHTS OB " GREEX BUG." 



ibs ::: life history a:nt> habits of aphelests. 



Mr. C. X. Ainslie made some observations on A s&nus nigrUus 

 at Mesilla Park. X. Mex.. in 1908. He states that when the adult is 

 ready to ovip : sit if approaches an aphidid very slowly and cautiously, 

 moving or swaving its body slightly from side to side and waving itfl 



antenna. When the antennae finally touch the plant-louse it st 

 turns suddenly about, moves backward slightly, and then gives the 

 victim a thru-: with its hairlike ovipositor. This operation appar- 

 ently causes pain to the aphidid, as she begins U kick up" her 

 abdomen and there sometimes appears a tiny drop of fluid where the 

 puncture was made. 



7::-. •;.; —I :.-L z^-^s^s :i 

 body of the spring grain- 

 i.z'z-3 :': - —'—_- - . Jr. 

 Apkethtus nigrihu has 

 emerged. Enlarged. 

 (OriginaL) 



Vt&.32.—Aplu1iuut *ewuflmrms,x parasite of the spring grain-aphis. Greatly 

 enlarged. «, Stigmal club, stiH more enlarged. (OriginaL) 



When the larva of Apkdinus nigritu-s is fully grown the body of the 

 plant-louse, according to Mr. G. G. Ainslie, turns black and the legs a 

 conspicuous white (fig. 33), while in individuals parasitized by A. 

 mail these appendages are black. The body, h : . of so small 



an aphidid as Toxoptera graminum appears to be but little swollen. 

 Mr. C. X. Ainslie found that under favorable weather conditions A. 

 mgriius developed from egg to adult in from 12 to 13 days. 



The following diagram will serve to illustrate the different hosts of 

 ApJiidiug testaceipes, A. avenapliu, A. confusus, Aplielinus maJi f 

 A. nigrituSj and A. which we have shown to attack 



optera graminum. This will give some idea of the numerous 

 sources from which an army of parasites may be recruited to oppose 

 any serious invasion of Toxoptera. 



