438 THE CANADIAN ENTOMOLOGIST 



According to Crosby's table of the North American species of 

 Megastigmus (Ann. Ent. Soc. Am., VI, p. 156, 1913) this species 

 runs down to M. lasiocarpi Crosby. I have rearranged his table 

 to include the present species as follows. 



TABLE OF SPECIES (FEMALES). 



1. Ovipositor not longer than abdomen 2 



Ovipositor longer than abdomen 3 



2. Stigmal club oval brevicaudis 



Stigmal club elongate physocarpi 



3. Front wings marked with a brownish spot adjoining the hind 



margin of the submarginal vein albifrons 



Front wings not so marked 4 



4. Stigma surrounded by a clouded area nigrovariegatus 



Stigma not surrounded by a clouded area 5 



5. Mesonotum black, with an oblong reddish orange area covering 



the posterior half of the middle lobe, the inner angles of the 



scapulae and axillae and all of the scutellum pinus 



Not so marked 6 



6. Black species 7 



Yellow species 9 



7. Pronotum with two yellow spots tsugce 



Pronotum black without yellow spots 8 



8. An elongate yellow spot on each side of the prothorax; length 



3.7 mm lasiocarpi 



Sides of prothorax black; length 2 mm laricis 



9. Axillae yellow; stigmal vein as long as the club is wide 



spermotrophus 



Axillae black except inner angle; stigmal vein shorter than 



width of the club , aculeatus 



In the fall of 1913 I also found the larva of Megastigmus 

 physocarpi Crosby in the seeds of Physocarpus opulifolius at 

 Ithaca, N. Y. It is similar in form to the larva of M. laricis, and 

 measures 1.9 mm. long by 8 mm. wide. The mandibles have four 

 teeth (Fig. 8). 



Explanation of Plate XXVII. 



1, M. laricis, female; 2, stigmal club of female; 3, stigmal 

 club of male; 4, egg; 5, larva; 6, mandible of larva; 7, head of 

 larva from in front; mandible of larva of M. physocarpi. 



