39 



Hair-worm parasite. 



Mcniiis acrydii ? — Qmt& an important internal enemy of 

 the destrtictive loctist of Argentina is a species of nematode 

 such as is ordinarily called a hair-worm. This parasite attacks 

 both tlie saltona and the voladora, and in each instance usuall}^ 

 tills the entire abdominal and thoracic cavities. It is white and 

 somewhat thicker than a hair from the tail of a horse, and 

 varies in length from 6 or 8 to as many as "■> centimeters. 

 L'sually but a single parasite of this kind infests the body of a 

 locust, tliough quite often there are tAvo, three or more. 



The entire life-history of these parasitical worms is not 

 definitely known, but the little we do know seems to indicate 

 the following mode of life : 



Fii;-. ''. — H;iir-\vonn parasite of ihe Schi^toc^rca 

 liaraiiijiisis, from phoioi^rapli. (original , 



" The Mennis acquires full growtli within its liost, and then 

 forsakes it by boring out with the head. X\\ the specimens so 

 leaving their victim are sexless, and are characterized b}^ a 

 mouth consisting of a very small aperture at anterior end, and 

 bv a minute anal point, which is usually covered. Unless they 

 are full-grown when the host perishes, or unless they reach 

 moist earth, these asexual worms perish; but if full grown, and 

 the}' succeed in reaching the surface of moist ground, they at 

 once bore into, and bury themselves out of sight. Here the 

 sexual organs are developed Irom a tatty body that the parasit- 

 ic form contains, and after undergoing one molt the perfect 

 and sexed form is assumed, and the anal end becomes rounded 

 and loses the minute point. Daring this underground life, no 

 food seems to be required, though several months elapse, and 

 the winter is passed before the animal procreates. '' ''' * ' 

 The female lays her eggs in the ground. The young, which 



3 



