THE CHALCIDOID GENUS PERILAMPUS. 37 



Examination of a considerable number of the Ilyplianti'ia cater- 

 pillars showed that the planidium could be found in almost any 

 portion of the caterpillar's anatomy, although they generally "floated 

 about" freely in the body cavity. Occasionally specimens attached 

 to the larval organs, such as the alimentary canal or silk glands, 

 were encountered. Further study of still younger caterpillars 

 revealed the most interesting and significant feature of the whole 

 life cycle, namely, the presence of the planidia wpon the exterior of 

 the caterpillars. These were apparently about to make their way 

 through the integument to the interior in a search for suitable hosts 

 upon wliich to complete their development. The less heavily 

 chitinized portions of the caterpillar's skin, that is, the portion 

 between the different segments, offered the most vulnerable point 

 of attack and almost invariably this was the place selected by the 

 parasite for making an entrance. IncUviduals which had not yet 

 started an opening were found quite as frequently upon the middle 

 of the segments as between them. Just how these planidia came to 

 be located upon the skin of the caterpillars and how, when, and 

 where the adult female Perilampus places her eggs, we have been 

 unable to ascertain up to the present time, and any statement in 

 regard to this portion of the life cycle must take the form of mere 

 conjecture. 



OVIPOSITION. 



There have been made, so far as published records go, at any rate, 

 no observations upon the oviposition of members of the genus 

 Perilampus. It is known, however, that oviposition does not occur 

 in the normal way, or in the manner we are accustomed to regard as 

 the normal method of oviposition among the parasitic Hymenoptera, 

 and for this reason speculations on what may actually occur are 

 rather interesting. 



In the first place it is obvious from the facts recorded in the pre- 

 ceding pages that Perilampus does not oviposit directly in or upon 

 its host. In the second place, it does not oviposit witliin the cater- 

 pillar of which its host is a primary parasite, which is equally obvious 

 from observations already made. That it. places its eggs upon the 

 young caterpillar is improbable, the adult Perilampus being too slow 

 and clumsy to be capable of accomplisliing this act with any degree 

 of certainty. 



There are two plausible methods wliich Perilampus might adopt 

 for the deposition of its eggs, and the writer is strongly incUned to 

 the view that one of these methods is in part at least correct. As 

 in the case of some of the parasitic beetles, it may deposit its eggs 

 upon flower heads or upon leaves of plants not in the immediate 

 vicinity of the caterpillar colony, the planidia hatching from these 

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