Severin and Severin—Habits of the Saw-fly . 
63 
amine a large number of specimens, or they would have 
noticed this individual variation. 
It is worthy of notice that the six-spotted specimens always 
had one pair of spots each on the fourth, fifth and sixth abdom¬ 
inal segments. Occasionally a specimen was found on which 
a pair of spots was very faintly indicated on either the third 
or the seventh segments. On these specimens the spots were 
usually small, and either circular or oval in outline. Those 
specimens which were marked with four spots on either side 
of the abdomen had usually one pair each on the third, fourth, 
fifth and sixth segments, the markings on the seventh segment 
usually being absent. Specimens marked with five spots on 
each side of the abdomen always had them on the third, fourth, 
fifth, sixth and seventh segments. Those specimens which were 
marked with eight or ten spots usually have those on the fourth, 
fifth and sixth segments in the shape of bands, covering the 
length of the segment and extending to near the dorsal median 
line of the abdomen. 
In the male we also found individual variation in color. 
Some of the specimens have the entire abdomen of a steel- 
blue color, while others have the anterior half of the abdomen 
steel-blue and the posterior portion reddish-brown. We ex¬ 
amined fifty males with the following results:— 
11 specimens with the entire abdomen steel-blue. 
39 specimens with the anterior half of the abdomen steel- 
blue and the posterior portion reddish-brown. 
Although but fifty specimens were examined, it is evident 
that those males having the abdomen partly steel-blue and 
partly reddish-brown greatly outnumber those having an en¬ 
tirely steel-blue abdomen. 
GENERAL, HABITS. 
The imago first makes its appearance about the beginning 
of June and disappears toward the middle of July. Both 
males and females are more active during the middle of a 
bright hot day of sunshine, flying about with a loud buzzing 
noise. As the air grows cooler, however, they become duller 
in all their movements. The males are usually found with 
