154 SEVENTEENTH Report STATE ENTOMOLOGIST OF MINNESOTA—1918 
verse diameter. The abdomen is closely applied to the thorax by its 
entire width. This condition is described by the expression “abdo- 
men sessile” (not stalked). The wings are folded over the abdomen 
when the insect is not in flight. 
The larvae are unmistakable; they are either slug-like and slimy, 
or resemble caterpillars very closely with the exception of having more 
than five pairs of prolegs. 
Larvae of this group need not be confused with caterpillars of 
Lepidoptera, for saw-fly caterpillars have from eighteen to twenty-two 
Fig. 28. Macrophya cassandra Kirby: female. 
prolegs and these have no circlet of hooks as in Lepidoptera. The 
former larvae move more slowly than the true caterpillars of the 
Lepidoptera and they frequently assume grotesque postures never 
taken by true caterpillars. When disturbed, they sometimes curl up, 
lying on their sides. They are in some species covered with slime, 
or exude a disagreeable liquid, and often change their color dur- 
ing larval life. 
Tenthredinid larvae generally change to the pupal stage in a 
cocoon. There may also be an outer 
cocoon, hard and coarse, and within that, 
one of finer texture. 
This group may perhaps be regarded 
as a connecting link between the Lepi- 
doptera and the Hymenoptera. 
The superfamily contains the most 
injurious individuals of the order. The 
species are largely confined to the tem- 
Fig. 29. EHiphytes mellipes - 
fc Norton; female. perate AoE: 
