TACHINA-FLIES AS LOCUST ENEMIES. 



319 



a letter from Mr. William H. Edwards, of Coalburgh, W. Va., gives an 

 interesting instance of this insect losing its way and being puzzled: 



I was greatly entertained one day at seeing this steel-blue dirt-digger ride a locust 

 up and down the walk of my garden in search of its hole, which it had missed by 20 

 feet, the hole being in fact in a walk parallel and sim- 

 ilar to the one it was on, but 20 feet away. The wasp 

 would ride uj) and down, stop, turn back, or drop the 

 'hopper and run about; then mount its prey again, 

 until it found out its mistake by getting at»last on to 

 the proper walk. 



Mr. A. N. Godfrey, one of our assistants, 

 observed this wasp sting a pupa of spretus 

 and bury it, and upon digging up the pupa 

 found the wasp egg at the juncture of the 

 hind femur with the body. Species of the 

 genu^ Scolia are also known to have this no. 58.— chloeion cceruleum. (Af- 

 same habit. ''' ^""'^-^ 



Tachina-flies.— The animals so far treated of as attacking the 

 locust either devour it bodily, suck its juices, or are parasitic upon it 

 externally. There remain those which prey upon it internally, and 

 which in time exhaust and kill it. The most common of these are the 

 larvae of certain flies belonging to the genus Tachina — gray-colored, two- 

 winged flies, having very much the general appearance of the common 

 house-fly, though usually somewhat larger. 



''These Tachina-flies firmly fasten their eggs — which are oval, white, 

 and opaque, and quite tough — to those parts 

 of the body not easily reached by the jaws 

 and legs of their victim, and thus prevent the 

 egg from being detached. The slow-flying 

 locusts are attacked while flying, and it is 

 quite amusing to watch the frantic efforts 

 which one of them, haunted by a Tachina-fly, 

 will make to evade its enemy. The fly buzzes 

 around, waiting her opportunity, and when the 



Fig. 59.— Teliow-tailed Tachi- , ^ / ^. ^ ^ ^ .' ,,, 



NA-FLY. (After Pdiey.) locust jumps or flics, darts at it and attempts 



to attach her egg under the wing or on the neck. The attempt frequently 

 fails, but she perseveres until she usually accomplishes her object. With 

 those locusts which fly readily, she has even greater difficulty ; but 

 though the locust tacks suddenly in all directions in its efforts to avoid 

 her, she circles close around it and generally succeeds in accomplishing 

 her purpose, either while the locust is yet on the wing, or, more often, 

 just as it alights from a flight or a hop. The young maggots hatching 

 from these eggs eat into the body of the locust, and after rioting on the 

 fatty parts of the body — leaving the more vital parts untouched — they 

 issue and burrow in the ground, where they contract to brown, egg-like 

 puparia, from which the fly issues either the same season or not till 

 the following spring. A locust infested with this parasite is more Ian- 



