136 PIMPLTXE ICHXEUMONIDAE 



massed together on a log in Maine. He attempted to cap- 

 ture them with his net, but they all flew away. Returning 

 to the same spot later, he found the males again assembled there. 

 This time he reached out and caught a number with his hand. 

 Upon being examined they were found to be males of both 

 M. lunator and M. greenei. The female, which later emerged, 

 proved to be a specimen of M. lunator. Whether there was a 

 female of M. greenei about to emerge near where the M. lunator 

 came out, or whether the males are unable to know in advance, 

 the species to which the emerging insect belongs, is a question. 



The dates of capture of the specimens of this species which 

 have come under my observation range from May 13 to Sep- 

 tember 30, although these are very probably not the outside 

 limits. 



Megarhyssa greenei Viereck 



Megarhyssa greenei Viereck, Proe. U. S. Nat. Mus., xl, p. 191, 9 cf . 

 Smith, Insects of New Jersey, 1909, p. 627. 

 Viereck, Proc. Ent. Soc. Wash., xiii, no. 2, p. 96. 



Type.— Cat. No. 13,499, U. S. N. M. 



Type locality: Harrisburg, Pennsylvania; female, June 25, 

 male, August 22, 1908. 



Megarhyssa greenei agrees with M. lunator except in the 

 following details. It has no dark lines extending from the 

 base of the antennae to the labrum. The band parallel to 

 the one in which the ocelli are imbedded, which in M. lunator 

 is dark brown or black, in M. greenei is but slightly darker 

 than the yellow ground color of the head. There is no 

 dark patch on the tip of the wings. The fusion of the sternum 

 and pleura extends about twice as far from the base of the second 

 abdominal segment as it does in M. lunator, reaching as far 

 beyond the spiracles as the distance from the base of the segment 

 to the spiracles. On the abdomen, the black bands which border 

 the yellow markings are continuous over the dorsum, but the 

 yellow band on the eighth segment is not continuous. The ovi- 

 positors are relatively shorter, being only from one to one and 

 a half times the length of the body. 



The description of M. lunator applies to the male of M. greenei 

 in all respects except those named above. 



For characters distinguishing this species from others in the 

 same genus, see list of distinguishing characters given after 

 the description of M. lunator. 



