1964] 
Porter — M elanichneumon 
133 
antennal flagellum [as compared to 37 to 38 segments in saevus 
(Cresson)], and its smaller size ± 9 to ± 10 mm. as against 13 
to 14 mm. 
Heleiobatos is also very distinct from brevicinctor (Say) in the 
male. The white maculations are more extensive, brevicinctor (Say) 
being entirely black except for its white scutellum and mark on 
gastral tergite 7. In structure the most significant distinction con- 
cerns the gastrocoeli, which in brevicinctor (Say) are shallow and 
conspicuously longer than wide, whereas those of heleiobatos are a 
little wider than long and comparatively deep. The characters of 
scutellar carination and sculpture described for the female also apply 
in general for the male, although there are some specimens of 
brevicinctor (Say) in which the dorsal areae of the propodeum are 
almost as smooth as in many specimens of heleiobatos. 
derivation of specific name: Heleiobatos is a Greek adjective 
signifying “inhabitant of swamps”. 
type locality : The type specimens were collected, all within a few 
yards of each other, at Metuchen, New Jersey, in a swampy area 
along the Lehigh Valley Railroad tracks just north of the bridge 
which carries the Reading Railroad across the Lehigh Valley. 
The locality is along a very small stream draining a pond. It is 
overshadowed by Salix discolor and supports a moderately thick 
ground cover of various grasses and clumps of Impatiens. Like the 
abundant tenthredinid sawflies and such ichneumonid genera as 
Cteniscus , Orthomiscus, and Smicroplectrus, which are also found 
here, M. heleiobatos appears to be a species of particularly moist 
habitats. This is in contradistinction to its close relative, M. 
brevicinctor (Say), which occurs commonly in a wide range of 
habitats from woods to the margins of fields. 
conclusions: Unless it should turn out to be conspecific with some 
Palaearctic form, M. heleiobatos is an easily recognized new species 
distinct from its relatives by ample characters of color and structure. 
The association of sexes is, of course, only tentative, but appears 
logical both from characters displayed by the specimens themselves 
and from the fact that all examples were obtained within a very 
limited area where no other M elanichneumon of similar aspect has 
been taken. 
Reference 
Heinrich, G. 
1962. Synopsis of the Nearctic Ichneumoninae Stenopneusticae, Part 5. 
Can. Ent. Suppl. 26: 578-634. 
