Parasitic Beetles. 413 



distances from land than the Calosoma would have to travel, 

 quite warrants this supposition. We have, however, another 

 undoubtedly British species, Galosoma inquisitor, of s mallei- 

 size and less beauty, which constantly frequents oaks for the 

 purpose of promiscuous feeding on the many Lepidopterous 

 larvge frequenting those trees. This habit of tree-haunting is 

 very rare among the large and predaceous Garabidai, which 

 usually prowl about on the ground, except occasionally at 

 night, when they have been observed investigating tree trunks 

 for their victims. Another of the Geodephaga, Zabrus gibbas, 

 a large, heavy, clumsy, black species, departs from the habits 

 of the members of that group so far as to be often seen climb- 

 ing up the shoots of young wheat and other plants. This has 

 been so frequently observed that it has been strenuously 

 urged that the beetle, unlike all its sectional allies, is a vege- 

 table feeder ; but the more reasonable view appears to be that 

 it frequents the plants for the purpose of preying upon the 

 numerous small insects of all orders found upon them. A 

 similar explanation accounts for the constant occurrence of one 

 of the burying-beetles, Silpha quadripunctata, upon young 

 oak-trees, where it finds a ready meal on plant-feeding larvee. 

 I have never found this insect in any other place than upon an 

 oak-tree ; though the other Silphce (except, perhaps, 8. atrata) 

 constantly occur in carrion. 



All the above cases of companionship, therefore, readily 

 admit of explanation, as also do certain of those hereafter men- 

 tioned, of some of which the entire life-history has, indeed, 

 been accurately chronicled. 



It will be observed that, in all the following instances, the 

 insects with which the beetles are associated belong to the 

 order Hymenoptera ; and it is in connection with the social 

 members of this order that the most constant and perfect — 

 though hitherto unexplained — cases of beetle-parasitism occur. 



The bees, to begin with, are affected by species of at least 

 three different genera, viz., Trichodes, Meloe, and Sitaris. 



The first of these, one of the Oleridce, has two reputed 

 British exponents, T. apiarius and T. alvearins, whose names 

 sufficiently indicate their propensities. Both of them are, 

 however, of exceedingly doubtful British origin, though 

 abundant on the continent; they are of moderate size, elon- 

 gate, bright blue with red bands, and very pubescent. T. 

 apiarius lives in its larval condition in the combs of the honey- 

 bee [Apis mellifica) ; whilst T. alvearius at a similar stage of 

 its existence inhabits the nests of mason-bees (Megachile 

 •niuraria, and others), though it has also been found under pine 

 bark. Both of them feed upon the larvas of the legitimate 

 owners of their temporary residences, and, in their perfect 



