50 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
other genera found in New England with the three under considera- 
tion. The species are numbered consecutively. Relations of species 
to each other when such are evident, are given in a paragraph immedi- 
ately before the name of the species. This paragraph is numbered 
the same as the species concerned, but the number is enclosed by paren- 
theses. In the case of species groups the discussion of characters 
precedes the description of the first species concerned, the parentheses 
enclosing the numbers of all. Data concerning species are presented 
in the following order: — name, bibliography chronologically arranged, 
location of types if known, summary of important characters, descrip- 
tion, habitat, general considerations and comparisons, and habits not 
previously reported. The description itself is divided into parts: 
head, its chaetotaxy; thorax, wings, legs, chaetotaxy; abdomen, 
and its chaetotaxy; genital segments; genitalia. Bristles of the legs 
and genital segments are considered under their respective headings. 
Only striking and important genital characters are given and char- 
acters of the fourth ventral plate which cannot be seen until the genital 
segments have been pulled out are mentioned under the same heading. 
It must be remembered in using the figures of genitalia for purposes 
of identification that the view presented is lateral, and paired parts lie 
one behind the other. Lobes and other movable processes of the penes 
very likely will not be seen in the identical position in which they are 
represented in the drawings, and individual variations in form are 
often found. The degree of chitinization also differs and variations 
are by no means rare. A posterior view of the forceps is given, but 
no attention should be paid to the shape of the base, the important 
point being whether or not the upward flap-like extensions are present. 
Forceps which normally have their prongs approximated may be 
slightly spread, due to the difficulty in pulling them from their hiding 
place uninjured. The fourth ventral plates are represented as seen 
from the ventral side, in most cases drawn from permanent mounts. 
If made from the entire specimen the edges of the fourth notum appear. 
No importance should be attached to hairy vestiture unless attention 
is especially called to it in the description. 
The color of the genital segments when otherwise than black, has 
previously been designated as "red" or "reddish." In this paper dull 
orange has been used as more nearly expressive of the actual color 
though no single color distinction will hold. Specimens which have 
been bred and immediately killed never shoAv the same color as those 
