i 9 2 ASSOCIATION OF ORGANISMS THE WEB OF LIFE 



wingless blood-sucking Fleas are here included. The modifica- 

 tions which they have undergone have no doubt been in relation 

 to the parasitic habit. 



BEETLES (COLEOPTERA) AS PARASITES AND BROOD-PARASITES. 

 To this order possibly belongs a family of small insects (Styhpida) 

 parasitic upon Bees, Wasps ; and, to some extent, upon certain 

 Bugs. Many zoologists, however, place them in a distinct order 

 (Strepsiptera). The adult female is little more than a shapeless 

 bag, living in the abdomen of a bee or other host, with one end 

 projecting externally (fig. 1137). The ^idult male, on the other 



hand, is a very active creature, possessing 

 large hind-wings, but only vestiges of fore- 

 wings. His free life is short, three days 

 being the maximum on record, while in some 

 species (of Xenos] fifteen to twenty minutes 

 is the limit, though during this brief period 

 extraordinary energy is shown. The nu- 

 merous eggs are developed internally, hatch- 

 ing out into minute six-legged larvae, which 

 make their way into the bodies of bee-grubs 

 or the like, though the way in which these 

 hosts are found is in many cases but imper- 

 fectly understood. Their presence in the 

 Fig. H37.-A Bee-Parasite (sty- interior of the grubs does not cause death, 



lops aterrinw} enlarged The fa ^y fe^ upon ^ f att SUD StanCe (fat- 

 male is shown above, the female * J \ 



(with two contained embryos) below body) between the various organs. Having* 



to right, and the larva below to left. ' ' 



once become parasitic they lose their legs 



and assume the appearance of minute maggots. Later on, when 

 the bee-grub passes into the pupa stage, the parasitic larva pushes 

 out one end to the exterior, and, if a male, also passes into the 

 pupa stage, but if a female, undergoes comparatively slight modi- 

 fications. When the adult bees come out of the pupae the male 

 parasites also emerge to lead their free existence, but the females 

 remain fixed in their hosts. Individual bees harbour but one or 

 a few of these curious parasites; in wasps they may be more 

 numerous. 



The parasitic habits of some of the Oil- Beetles (Meloidce) are 

 both remarkable and highly interesting. Fabre has worked out 

 the life-history of one species (Sitaris humeralis, fig. 1138), of 

 which the larvae feed on the eggs and honey of certain bees 



