Asilidae. 5 



cell, and the Dasypogoninae wilh a few exceptions also include the 

 weaker, generally more slender forms with often less strong legs; these 

 forms take weaker prey. The Laphriinae and Asilinae are strenger 

 and generally more bristly, and they fly very well; they are therefore 

 the strongest robbers, often attacking rather strong and large prey. — 

 There is a work of Poulton (Trans, of the Ent. Soc. of London, 1906, 

 323) on the prey of Asilids w^hich is of some interest. The author 

 maintains that there is mimicry between Asilids and their prey, but I 

 do not think this is correct, and I have not at all found it confirmed. 

 In the foUowing I shall give what is known to me about the prey of 

 the single species. — As said before, the hypopharynx is used to sting^ 

 with and it is used when the fly attacks. It may be plunged through 

 ]-ather hard chitin ; it is thus recorded that an Asilus stuck it through 

 the elytra of a lady-bird, and Asilids have been captured with species 

 of Hister as prey. Whether the Asilids are in possession of a poison 

 or not is not known, but it is recorded (f. inst. Poulton, 1. c. 365, 

 foot-note), that the prey collapse instantaneously, and I have made 

 the same observation myself, so that the action of some poison is 

 very probable. Zeller (Isis 1840, 34) says that they have a poisonous 

 saliva but gives otherwise no definite information; he says also that 

 they may use the mouth parts for defence and he continues: „Der 

 Stich ist zwar empfmdlich genug, verursacht aber wohl nie Geschwulst." 

 Riley (First Rep. of the U. S. Ent. Gomm. 317) remarks about the 

 American species Froctacanthns milberfi Macq. that they „have a suf- 

 ficiently powerful beak to produce quite a severe sting on the human 

 hånd." — The species of Asilids occur in many different localities, both 

 in woods, some especially in pine-woods, on fields, heaths, at the shore 

 and in downs, but most species always seek dry and sandy districts; 

 some generally prefer stems and piles, others the sandy ground. The 

 weaker forms generally occur in herbage and high grass. 



From the palæarctic region about 500 species are known and 

 from North America about 550; I find only one, Laphria gilva, common 

 to both regions. 



I am aquainted with no case of parasitic Hymenoptera from 

 Asilids, and so far as I am aware none is recorded in the literature. 



Aslids earlier recorded from Denmark. — Kramer in 1760 (Spec. 

 Insectol. Dan.) records two species : A. crabroniformis and ater. Brijn- 

 niche in 1761 (Prodr. Insectol. Siælland.) has three: A. crabroniformis, 

 ater and forcipatus. In 1763 (Pontoppidan, Dansk. Atl. I) he has 7: 

 A. crabroniformis, ater, gilvus, germanicus, forcipatus, tipuloides and 

 oelandicus. Noting more can be said about these species than that 

 they are Asilids and identical with some of our species; probably 



