6 Kev. T. A. Marshall's monograph of 



Smith, fi'om Japan (which, however, is not a true Bracon) 

 has the body f inch long, while the terebra attains the 

 extraordinary length of 6f inches. 



Great pains have been taken to collect information 

 respecting the parasitism* of these insects. A number 

 of bred specimens, amounting to some hundreds, has 

 been kindly contributed by various entomologists, Big- 

 nell, Billups, Bridgman, Cameron, Fitch, J. E. Fletcher, 

 W. H. B, Fletcher, and others. In all such cases no labour 

 has been spared to identify species correctly. The 

 names of lepidopterous victims are taken from ' The 

 Entomologist Synonymic List of British Lepidoptera,' 

 by E. South, Loudon, 1884. For notes and references 

 derived from published works, as those of Eatzeburg, 



* Parasitism is a somewhat vague term, but may be divided into 

 the incomjdete, as that of the cuckoo, &c., and the complete, as in 

 the case of hymenopterous insects. A complete parasite is an 

 animal which lives inside or upon the body of another larger than 

 itself, devouring its substance and causing it to perish. The 

 Ichneumons in general are well known to be internal parasites ; 

 yet Brischke's observation respecting Oncojjhanes reported by 

 Ratzeburg and to some extent confirmed by Bignell, tends to the 

 conclusion that at least some of the Braconidce are external com- 

 plete parasites. Whatever doubt may be considered to attach to 

 this circumstance, we miist hesitate still more to receive the 

 accounts published of the occurrence of Braconidce, otherwise 

 known to be parasites of Lepidoptera, among spiders' eggs. These 

 are minute bodies, and any larger insect preying upon them must 

 be external, and must devour many ; in which case it is no more 

 a parasite than any other cai'nivorous creature. Hence Brischke's 

 statement that he has bred the large Microgaster deprmiator, 

 Nees, from spiders' eggs, seems inadmissible. Ruthe conjectured 

 the same Microgaster to be a parasite of Domhus terrestris, L. It 

 is hard to believe that whereas the other larva; of tlie genus are so 

 organised as to breathe and live by suction within the body of a 

 caterpillar, surrounded by humidity and protected from atmospheric 

 influence, this one alone should live in the spider's nest exposed, 

 preying upon eggs, without being subject to the conditions of 

 parasitism. Pezoniaclms, however, may readily be quoted as a 

 received example of an Ichneumon bred from spiders' eggs ; in 

 which case it must be an external feeder, and not a true parasite. 

 It is, however, much more commonly and certainly obtained from 

 the cocoons of Microgaster, being then distinctly an internal 

 parasite. The history of Pezoniaclms is not yet cleared up, nor 

 can we deny (whatever difficulty may exist) that it has proceeded 

 from spiders' nests. It behoves future observers, however, to 

 make very sure that the supposed spider's nest is the genuine work 

 of an araneid, and to verify the species. For Ajiantelcs congcstas, 

 Nees, and other Microgasterids make nests of cocoons which have 

 often been mistaken for the work of spiders, and the breeding of 

 Pczomachiis, llcmitclcs, &c., from these is a common occurrence. 



