1 890.] 



ENTOMOLOGICAL NEWS. 



writers refer to this sclerite as M? scutellum. Of the four sclerites 



which compose the tergal portion of 

 each thoracic segment, the scutum is 

 usually the largest; the scutellum is the 

 second in importance ; while the prae- 

 scutum and the post-scutellum are fre- 

 quently but little developed' ' (Comstock) 

 The sternum consists of but one 



Fig. 10. Diagram of a thoracic sclerite. 



segment (after Comstock). The sderites of the ple urum are the 



a, prfescutum ; o, scutum ; c, 



scutellum ; d, post scutellum ; e, episternum and the epimeron, and some- 



episternum;/, epimeron :jf , par- timeg a th}rd fa> parapterOH. Their 



apteron ; z, sternum ; a, 6, c and d, _ _ _ 



taken together form the tergum ; position IS shown in fig. IO. The par- 



e, f and g, taken together form apt eron in different groups of insects 



the pleurum. 



has also been called the tegula, scapula 



and patagium. The thoracic spiracles* pierce a small piece of 

 the pleurum called the peritreme. 



Attached to the thorax are the organs of locomotion the legs 

 and the wings. 



The leg, or the foot of an insect, as it is indifferently called, 

 consists of five parts, the coxa, trochanter, feimir, tibia and tarsus. 

 The coxa, or hip joint, is the basal part, and is attached to its 



thoracic segment near the lateral border of 

 the sternum, sometimes so firmly as to be im- 

 movable. A small sclerite is sometimes found 

 between the coxa and the epimeron, called 

 the trochantin. The trochanter is between 

 the coxa and the femur, or thigh. The fourth 

 part is the tibia, or shank, and the terminal or 

 fifth part is the tarsus, consisting of from one 

 to six joints. Usually the leg of an insect is 

 armed with spines, or clothed with hairs. 

 The spines at the apex of the tibia are usually 

 longer than the others, and receive the dis- 

 tinctive name of tibial spines, or tibial spurs. 

 The last joint of the tarsus bears one or two tarsal claws, nails, 

 or unguiculi. On the ventral surface of the joints of the tarsus 

 are often ' ' cushions of short hair or of membrane, capable of 



Fig. ii. Leg of an 

 insect. 



a, coxa; />, trochanter; 

 c, femur; d, tibia; e, 

 tibial spurs ;_/", tarsus of 

 five joints; g, tarsal 

 nails. 



: See page 71 of this volume of ENTOMOLOGICAL NEWS 



