J. H. MERRILL 135 



one in which the ocelli are imbedded, dark patches on the tips 

 of its wings, which characters are absent in greeyiei. In lunator 

 the fusion of the pleura with the sternum of the second abdominal 

 segment extends to or but slightly beyond the spiracle, while 

 in greenei it extends as far beyond the spiracle as the distance 

 between the spiracle and base of the segment. In lunator the 

 dark bands on the abdominal segments are not continuous 

 over the dorsum, while they are in greenei. On the eighth seg- 

 ment of lunator the yellow band is continuous but this condition 

 does not occur in greenei. In lunator the ovipositors are relatively 

 longer than in greenei, being from two to two and a half times 

 the length of the body, and in greenei from one to one and a 

 half times. 



Lunator may be distinguished from nortonii by the shape of 

 the markings on the 4th, 5th and 6th abdominal segments. 

 In lunator they are acutely angulated bands, while in nortonii 

 they are roundish spots. The wings of lunator are hyaline, with 

 dark spots, while in nortonii they are transparent, fuscous and 

 with no dark patches. It can be distinguished from mexicana 

 in that the latter is bright yellow marked with black. The 

 apical margins of the abdominal segments of mexicana are bor- 

 dered with black bands continuous over the dorsum. The 

 areolet of the fore wings of mexicana is absent. It also has a 

 dark patch on the tip of the fore wing but none in the region of 

 the stigma. Mexicana has no dark lines from the base of the 

 antennae to the labrum. 



Lunator may be distinguished from atrata, humida, canadensis 

 and nitida by the fact that in these forms the greater part of 

 the surface of the body is black with white, yellow or fuscous 

 body markings. 



This species is widely distributed throughout the United 

 States and Canada. It is found in abundance on trees and logs 

 which are infested with Tremex, working in company with M. 

 atrata and M. greenei. They appear earlj'- in the summer and 

 throughout the whole season may be seen crawling about, seeking 

 a favorable spot for ovipositions. After laying its egg the insect 

 is often unable to extricate its ovipositor and is held a prisoner 

 by it until death. Mr. C. W. Johnson, Curator of the Boston 

 Society of Natural History, observed a large number of males 



TRANS. AM. ENT. SOC, XLI. 



