62 



PSYCHE. 



[April 1894. 



Copenhagen Entomologiske meddelel- 

 ser, vol. 3, 1S91. 



As a familiarity with the Danish 

 language is not one of my accomplish- 

 ments, I am indebted to Mr. Martin 

 Linell for a translation of some of the 

 more important portions ; and as Mr. 

 Wesenberg has discovered many ne\v 

 and important facts in regard to the 

 life history of this species, in many 

 respects totallv at variance witli the 

 habits of all other fossorial wasps whose 

 habits have been investigated. I feel 

 sin-e a resitmtt of them here will be 

 appreciated by my readers. 



It makes its cell two or three inches deep 

 in solid sand covering it up with loose sand 

 and generally also with a little flat stone to 

 prevent parasites from gaining access to the 

 larva. The cell measures one cubid inch, 

 the entrance tunnel being one and a half 

 centimeters long and arcuate. A cell con- 

 tains four or five fresh flies {Lucilia., E/-is- 

 talis, etc.) and torn off wings, sucked out 

 thoraces, etc., and in the middle of these a 

 big flat larva. 



All other digger-wasps furnish the food 

 for their young once for all, either first lay- 

 ing their egg, then putting in food, or first 

 filling up the cell with food, then laying 

 their egg on it, and covering the whole with- 

 out again visiting their cell or seeing their 

 larva. Such, however, is not the case with 

 Bembex rosti-ain, for just as soon as the 

 larva has hatched, the female makes visits 

 to it several times a d.ay bringing each time 

 a fresh fly for its larva. 



Bembex, according to Wesenberg. lacks 

 the power of paralyzing its prey and all the 

 flies are dead and show deep marks on the 

 thora.\ just above the tegulae, made by 

 strong jaws of the wasp. 



In two cases, he found the eggs laid on a 

 single fly PoUenia. When the larva is 

 hatched the mother brings more and more 



flies, the flies brought being larger and 

 larger as the larva grows. With a larva not 

 quite grown he found 4 Eristalis, 6 Syrphus, 

 2 Musca, and 3 Anthomyia flies. 



The fully grown larva was of a greyish 

 white color 24 centimeters long, with the 

 segmentsbehind the head gradually expanded 

 to the last segment. 



Fabre took a young larva, fed it on flies, 

 and before pupating it had devoured 82 flies. 



He also says that 50 Beinbecids will nest 

 on a spot as big as a room, during a period 

 of three months, the period for the develop- 

 ment of each larva being two weeks. This 

 will allow only five or six young ones for 

 the season. But does each female have more 

 than one nest.' If so, how can it remember 

 them.' Mr. Wesenberg then tells how the 

 larva forms its cocoon, quoting from Fabre, 

 and follows with some remarks about the 

 circle of small holes about the middle over- 

 looked by Fabre. 



As Dr. Riley has called special attention 

 to similar holes in the cocoon made by 

 Sp/ieciiis speciosns without satisfactorily 

 explaining the reason for them, I give below 

 what Wesenberg says about the formation 

 of the cocoon and the reason for the exist- 

 ence of these holes. 



The larva spins its cocoon thus : It first 

 pushes all the remnants of food into a corner 

 of its cell, spins fine white silk threads to all 

 the walls, makes a net of pure silk supported 

 by these threads, closed and tapering at one 

 end but kept open at the other end by threads 

 to the walls of the cell. Then the larva pro- 

 trudes its head and scrapes sand from the 

 wall; when it has a lump large enough it 

 brings it by the mouth into its net and dis- 

 tributes the sand-grains uniformly over the 

 inside with silk as cement. The outer side 

 is then prepared with still greater care. 

 Sand-grain after sand-grain is carried out 

 and glued on, until the white silk cocoon is 

 transformed into a dark brown sand cocoon. 

 The sand lump is now used up, but still the 

 cocoon is lacking a cover. A new lump of 

 sand is now scraped together, taken inside 



