42 CROP PEST COMMISSION OP 



so as to form distinct brown spots. The species is widely distributed 

 over the southeastern United States. In Louisiana it has been taken 

 as follows: Negreet, May 19; Leesville, June 2 (Hardy); Merryville, 

 June 2 (Martin); Houghton, June 20, 1905 (Garrett). So far as ob- 

 served the adults occur in the early part of the season only. The 

 larger specimens are seven-eighths of an inch in length, but the 

 Louisiana specimens I have seen are somewhat smaller. 



CONCLUSIONS. 



Since there is a great deal yet to learn about horseflies, it 

 seems proper to call attention to a few points worthy of special 

 consideration. 



Predacious and parasitic insects which prey upon horseflies 

 are capable of doing much towards checking the ravages of 

 certain species. Who knows but what these natural enemies of 

 the flies could accomplish much more if conditions were more 

 to their Jiking? The work of the horse guard (Monedula Caro- 

 lina) is especially efficient, and since it appears that this species 

 thrives in certain sections where there is sand for it to make 

 its nests in, could it not be introduced into places where it is 

 not known at the present time? If more were known of its habits 

 and requirements, life history, and enemies, it might be possible 

 t > increase its numbers in sections where it is now present but 

 not plentiful enough to do the work desired of it. 



Before it is possible to speak intelligently concerning what 

 may be accomplished in the way of combatting any injurious 

 insect or group of insects, a full knowledge of each species is 

 usually necessary. The codling moth of the apple could not be 

 handled successfully until a careful study of its life history 

 showed that the young insect entered the calyx end of the apple 

 in the spring, and that if this part of the apple were thoroughly 

 sprayed with the proper mixture before entrance was effected, 

 it would receive a fatal meal the first thing; but that if spraying 

 were deferred until after it entered, the insect could not be 

 reached. 



Not over a dozen of the North American horseflies are 

 known in their immature stages, the eggs of less than ten species 

 have been described, and the larva? of some of the most abundant 

 and injurious forms remain unknown. When we consider" that 



