128 Mr. F. Smith's Contribution 



hood of London, tliat not more than one male Stylops occurs to 

 twenty females ; supposing this to be the case, and that each 

 female Stylops produced six thousand larvae, which is within the 

 calculation made by Mr. Newport in his " Natural History of the 

 Strepsiptera," we should have a total result of one hundred and 

 fourteen thousand larvae of Stylops, ofiA this from the nineteen in- 

 dividuals which we captured alone; were it not that few of these 

 ever attain their perfect condition, surely our only difficulty would 

 be to find a bee not infested by a parasite. 



The explanation of this apparent difficulty will be perhaps best 

 given to those who have not investigated the subject, if I relate 

 my observations on a female o{ A. Trhnmerana, which was infested 

 by a female Stylops. The Andrena had been kept six or eight 

 days in 9. box covered with fine net, she had been well supplied 

 with fresh. flowers, and was very active and apparently healthy; 

 my notice was attracted by observing the bee running about ap- 

 parently in a very excited state, burying herself beneath the leaves 

 and flowers, then issuing forth and running round the sides of the 

 box ; sometimes she would stop, bury her head in the petals of a 

 Dandelion, and then commence brushing herself with her posterior 

 legs, passing them quickly over the upper surface of the abdomen; 

 these unusual movements on the part of the bee led me to examine 

 her more closely. I then found that she was covered with hun- 

 dreds of the larvae of Stylops, and her brushing and excitement 

 was caused by efforts, on her part, to free herself from the annoy- 

 ance which the host of larvae evidently occasioned her. There 

 can be little doubt of hundreds, nay, thousands of the larvae being 

 brushed off" in situations, where, from want of sustenance, they of 

 necessity perish; whilst others, falling into the petals of flowers, 

 may attach themselves to bees which subsequently visit them to 

 extract their sweets ; whilst others, fixing themselves to insects of 

 other orders, are removed from the chance of finding a situation 

 in which proper sustenance would enable them to attain a state of 

 maturity. 



Altliough Stylops is at present considered a rare insect, parti- 

 cularly the male, I have no doubt it will be found in abundance 

 when once the proper locality is discovered and diligently searched 

 by a competent Entomologist. I have never had the good fortune 

 to discover a colony of Andrena convexiuscula, a bee which ap- 

 pears to be always infested, or I feel pretty certain 1 should have 

 obtained Stylops in plenty. All the specimens which I possess of 

 A. convexiuscula, those in the National Collection, and all which 



