%9r'] PROCKEDINGS OP THE NATIONAL MU.<i:rM. r)Ml 



of E. spilosomatis ]\IS. iirc roiiiid altadicd in a ;4hiiip aiiioiij; tlir Ion;; 

 liairs on the dorsum of tlie alxlonu'n of tlic larva of Spilosunid rirtjiitiva. 

 In the allied gemis Mhttopis, M.platijnota' transfornjs witliotit its host in 

 , the leaf rolls of Platynotd rostKoia, as observed by Ilubbanl (Oran;,M' In- 

 sects, p. 153). 



Euplectrufiy although it spins silk, can by no means be said to form a 

 cocoon, and therefore does not form a true exception to the rule that tiie 

 pupa' are naked with the ('li(ilvi(U(](r. The oft-repeated and hitheito 

 accepted observation of Ilaliday, to the eil'ect that Cori/)i(( clnnitd docs 

 spin a true cocoon, would, how'ever, form a distinct and unexjdained ex- 

 ception were it not for the fact that I fully believe the statement to have 

 been unfounded, llaliday, in speaking of jdant-louse j)arasites (l']nlom. 

 Mag. II, 00), writes: "Some of these last [parasites of Aphidius] {Coninti 

 clavata Walk., Ent. Mag. i, p. 380), not content with the covering whicli 

 protects the Aphidius to its linal change, wiien they are full fed leave 

 the cavity and spin a white silky web between the belly of the Puceron 

 and the leaf, and in this undergo their transformation." 



This statement has been (pu)ted by Westwood in his Introduction and 

 by subsequent writers, and Bucktou, in Vol. ii of his Monograi>h of the 

 British Apliides, gives a somewhat elaborate illustrated account of the 

 cocoon-spinning of a species which he calls C. dubia. He figures one 

 cocoon broken open and showing several shining black pup;v which he 

 considers to be parasites of the Gonjna. Coryna, it nuiy be stated, is 

 identical with the Pteromaline genus racJu/crcpis of Foerster. Now 

 cocoons precisely similar to those described by llaliday and figured by 

 ])Uckton are found in this country. Miss Murtfeldt has found them 

 under a roseaphidid in Missouri, and Dr. liiley tells me that he has seen 

 them abundant under dead aphides upon his rose bushes in \\'ashing- 

 ton. We breed from these cocoons here not Pacht/crcpishiit the aphidiid 

 genus PrrtOM, and as it is (piite out of the question that Vriion shoiUd be 

 hyperparasitic upon Paclnjoepis, we may safely conclude that Prami 

 makes the cocoon and that Pachyrrcpis (or Coryna) is a hyperparasite. 

 It is nuire than likely that the several pupa' of the unknown secondary 

 parasite figured by Buckton are those of Coryna itself, wliile the larva 

 which he watched so carefully under glass and figured in the act of 

 makiuff its cocoon was undoubte<llv braconid and not chalcidid. \Ve 

 have then no cases in which a chalcidid larva transforms to pni)a witiiin 

 a true cocoon. 



now MANY DEVKLOl' IN A SINGLE HOST? 



The answer to this qiu'stion is brief — from one to three thousand! 

 With the larger species but one individual issues from a single h(»si mm 

 less the latter is of extraordinary size. No more than one specimen of 

 Chalcl'i robusta issues from the chrysalis of a swallow-tail butterlly, but 

 with Spilochalcis m(i)i((\ a parasite of nearly ecpial size. Chambers reared 

 •iS from a single cocoon of the large American Silk-worm TcUa poylphe- 



