2828 Insects. 



of considerable power being required to detect the apterous females. So many inte- 

 resting particulars are connected with the development of the parasites and their 

 victims, that every fact should be carefully recorded. 



From the observations which I have made it appears that the eggs of Stylops do 

 not arrive at maturity until fourteen or sixteen days after the impregnation of the 

 female. On the 27th of April, 1849, I captured a female of Andrena Trimmerana. 

 I observed the bee struggling and turning over and over on a gravel pathway, and 

 picked it up : in doing so I observed a small insect take its flight, evidently from the 

 bee : this I have no doubt was a male Stylops, its flight and white appearance exactly 

 agreeing with Mr. Dale's description : unfortunately I could not succeed in capturing 

 it. On examining the bee, I found a cocoon remaining between the abdominal seg- 

 ments, the cap of which was pushed off: this I recognised as being the cocoon of a 

 male Stylops : the bee was also infested by two females. In fourteen days from the 

 time of capture the little hexapods began to appear, at which time the bee died : these 

 minute larvae T found had the power of existing without food from six to eight days 

 in confinement, and would probably have lived even longer in their natural position. 

 These parasites do not appear to infest any of the very pubescent species of bees, but 

 there is one remarkable peculiarity worthy of observation : when the bee attacked is 

 one of a species which undergoes its metamorphosis and arrives at the perfect state 

 in autumn of the same year, passing the winter in a dormant state, the parasite un- 

 dergoes its changes simultaneously with the bee ; and in the case of such species as 

 pass the winter in the larva state, the development of the Stylops is also retarded un- 

 til the final change of the bee takes place, both arriving at maturity at the same 

 period. Of the genus Halictus, I have met with infested individuals both in spring 

 and autumn ; so that of the genus Halictophagus there must be two broods in one 

 season. 



The first stages of development in Stylops will probably ever remain a mystery ; 

 the exceedingly minute size of the larva — too small to be observed by the naked eye 

 — will probably render observation impossible. I should myself incline to the opinion 

 that it is at all periods of its existence carnivorous ; and probably it will be found 

 that its allied parasite, Meloe, is on the contrary at all times herbivorous, at least 

 feeding on vegetable productions, — on pollen in its larva state, and on Ranunculaceae 

 in its adult condition : this however requires proof. I have myself more than once 

 endeavoured to clear up the matter, but hitherto without success : I am, however, 

 about to renew my experiments. Mr. Newman records (Zool. 1801) the results of 

 his experiments, in observing the development of the eggs of Meloe : he says, " I 

 watched the eggs day by day, and at last had the satisfaction to see them produce 

 minute active little larvae ; in fact they were the Triungulus Andrenatarum of Dufour 

 and the Pediculus Melittae of Kirby." I have on several occasions reared the larva, 

 but I never found the Pediculus Melittae developed. Were Mr. Newman's larvae the 

 black Pediculus of Kirby ? or the bright orange larvae described by Mr. Newport as 

 those of Meloe violaceus and M. proscarabseus ? which never become black, and 

 which in fact are much smaller than the Pediculus. This Pediculus Melittse is with 

 me a perfect enigma. I find it very abundant at Hampsteacl in flowers, and also on 

 bees. It does not appear to be the larva either of Meloe violaceus or of M. prosca- 

 rabaeus, the only two species found in that locality : now what can it be the larva of? 

 doubtless of some insect by no means uncommon : that it is not that of either of the 

 species of Meloe I feel pretty certain. I have fed them with fresh flowers, aiu' kept 



