ASILUS-FLIES VS. COTTON- WORMS. 171 



simple in their structure, more firm, stout, arid powerful. lu the horse-flies the trunk 

 or proboscis ia soft, flexible, and sensitive ; here it is hard and destitute of feeling a 

 large, tapering horn-like tube, inclosing a sharp lance or spear-pointed tongue to dart 

 out from its end and cut a wound for it to enter ; this end, moreover, being fringed 

 and bearded around with stiff bristles to bend backward and thus hold it securely in 

 the wound into which it is crowded. 



The proboscis of the horse-fly is tormenting, but this of the Asilus-flies is torturing. 

 That presses its soft cushion-like lips to the wound to suck the blood from it ; this 

 crowds its hard prickly knob into the wound to pump the juices therefrom. It is said 

 Asilus flies sometimes attack cattle and horses, but other writers disbelieve this. * * * 

 Certain it is that these flies nourish themselves principally upon other insects, attack- 

 ing all that they are sufficiently large and strong to overpower. Even the hard crus- 

 taceous shell with which the beetles are covered, fails to protect them from the 

 butchery of these barbarians. And formidably as the bee is equipped for punishing 

 any intruder which ventures to molest it, it here finds itself overmatched, and its 

 sting powerless against the horny proboscis of its murderer. These flies appear to be 

 particularly prone to attack the bees. Eobineau Des Voidy states that he had repeat- 

 edly seen the Asilus diadema, a European species somewhat smaller than this of Ne- 

 braska, flying with a bee in its hold. But it probably does not relish these more than 

 it does other insects. We presume it to be because it finds them in such abundance 

 as enables it to make a meal upon them most readily, and with least exertion, that 

 these flies fall upon the bees and rose-bugs. And so large as they are, a single one will 

 require perhaps a hundred bees per day for its nourishment. If these flies are common, 

 therefore, they will inevitably occasion great losses to the bee-keepers in that part of 

 the country. 



Since the foregoing account was written, Mr. Thomson has favored us with another 

 communication giving some most interesting observations upon the habits and destruc- 

 tiveness of this insect, which we here append in his own words. He says: 



" After sending you the specimens I watched its proceedings and habits with much 

 care, and found that, in addition to the honey bee and rose bugs, it devours many 

 other kinds of beetles, bugs, and flies, some of which are as large again as itself. It 

 appears to be in the months of June and July that it is abroad npon the wing, destroy- 

 ing the bees. None of them are now (August) to be seen. When in pursuit of its 

 prey it makes quite rapid dashes, always capturing the bee on the wing. When once 

 secured by wrapping its legs about it, pressing it tightly to its own body, it immedi- 

 ately seeks a bush or tall weed upon which it alights and commences devouring its 

 prey by eating (piercing) a hole into the body, and in a short time entirely consuming 

 it (sucking out the fluids and soft internal viscera) and leaving only the hard outer 

 skin or shell of the bee. Upon the ground, beneath some favorable perch for the fly 

 near the apiary, hundreds of these shells of bees are found, accumulated in a single 

 day. Whether the work of one fly or of several I am not able to say. I have just 

 returned from a professional tour through the northern part of our territory, taking 

 nursery orders, and in many things this business and the apiary are closely connected. 

 In no case have I found a hive of bees that has thrown off a swarm this season! The 

 dry weather, bad pasture, and other reasons were assigned as the cause. But many 

 persons, since they have found this fly at his work of destruction, now believe it to 

 be the cause of this non-swarming of the bees ; and I am led to the sama opinion. I 

 have only to add further that this bee -killer delights in hot dry weather, and it is very 

 invulnerable and tenacious of life. I have observed the honey-bee and also the hornet 

 sting it repeatedly, but with no other effect than to cause it to tighten its hold upon 

 them. Once when I forced the assassin to release his prey, he gave me such a wound 

 in the hand as has taught me ever since to be very cautious how I interfere with 

 him.'' 



Mr. Thompson, in an article in the Kural World for September 12, 

 18GS, stated that he had observed one individual Asilus-fl y to destroy 

 141 bees in one day. 



