ANATOMY AND PHYSIOLOGY 55 
as in Stenobothrus and such other Acridiidz as stridulate by 
rubbing the femora against the tegmina. 
Legs of Larvze.—Thoracic legs, terminating in a single 
claw, are present in most larve. Caterpillars have, in addi- 
tion, fleshy abdominal legs (lig. 64) ending in a circlet of 
hooks. Most caterpillars have five pairs of these legs (on 
abdominal segments 3, 4, 5, 6 and 10), but the rest vary in 
this respect. ‘Thus Lagoa has seven pairs (segments 2—7 and 
10) and Geometridz two (segments 6 and 10), while a few 
caterpillars (Tischeria, Limacodes) have none. Larve of 
Mechanics of an insect’s leg. a, axis of coxa; c, coxa; cl, claw; e, extensor of 
tibia; ec, extensor of claw; et, extensor of tarsus; f, flexor of tibia; fc, flexor of 
claw; ft, flexor of tarsus; 7, r, rotators of coxa; s, spur; t, trochanter muscle (elevator 
of femur); ti, tibia.x—After GRABER. 
saw flies (Tenthredinide) have seven or eight pairs of abdom- 
inal legs and larve of most Panorpide, eight pairs. Not a 
few coleopterous larve (some Cerambycide, Phytonomus) 
also have abdominal legs, which are incompletely developed, 
however, as compared with those of Lepidoptera. 
The legless, or apodous, condition occurs frequently among 
larve and always in correlation with a sedentary mode of life; 
as in the larve of many Cerambycidz, nearly all Rhynchoph- 
ora, a few Lepidoptera, all Diptera, and all Hymenoptera ex- 
cept Tenthredinidze, Siricidee, and other Terebrantia. 
