70 



INSECTS ABllOAD. 



doubtless observe the remarkable shape of the wings. 

 Instead of having the upper 

 edge nearly straight, as is 

 the usual custom with in- 

 sects, it is much thickened 

 in the middle, and formed 

 into an angular projection. 

 The length of the insect is 

 rather less than half an 

 inch. 



The remarkable fly which 

 is given in the accompany- 

 ing illustration inhabits the 

 United States. 



It is called Militaris, be- 

 cause in its larval state it 

 is parasitic on the " Army 

 Worm," i.e. the caterpillar of Lmcarict unijnmctata, which 

 traverses the country in vast hosts, completely devastating 

 whole fields of the grain and grass crops. Nothing stops them 

 but a deep ditch with perpendicular sides, and when such a 

 ditch is cut across their line of progress, it is often found filled 

 to a considerable depth with 



a seething, moving mass of i 1 



larvw. 



Many stupid people, on 

 seeing the Exorista emerge 

 from the Army Worm, took 

 it into their heads that it 

 was the parent of the cater- 

 pillar, and so destroyed 

 every fly they could catch, 

 instead of protecting the in- 

 sect as their best friend. 



It is also parasitic on the 

 larva of Atfacus Cccropia, 



which feeds on the apple, cherry, plum, and otlier fruit trees. A 

 peculiarity of this insect is, that instead of causing the larva 

 which it infests to decrease in size, it has just the opposite effect. 



-Exoiista militans. 

 (Dark silver-grey ) 



