AN EXPLANATION OP . 
354 
Spiracula, the respiratory organs, situated on the sides of the abdo- 
men. 
SquamulajO Scale ; an erect membrane placed between the thorax and 
abdomen. 
Stemmata, the Ocelli or little eyes placed on the summit of the head : 
these are frequently considered in the character of a genus. 
Sternum, the ridge running under the breast; this part is very con- 
spicuous in the Dytkidie. 
Stigma, a spot or mark generally on the upper wing. 
STRIA, a longitudinal line, and often punctured, generally extending 
from the base to the apex of the elytra. 
Obsolete i, indistinct, as if obliterated. 
Striga, a narrow transverse line. 
Sulcus, a deep hollow furrow. 
Sutuba, the part where the elytra meet and form the line in the tnid- 
dle of the back, from the base to tire apex. 
Tarsus, the Foot. The form and number of the joints vary according 
to the insect's mode of life : in several species of the Coleoptera the 
anterior tarsi of the male are frequently broader than ihose of the 
female, and consequently serve as a sexual distinction. The num- 
ber of joints in the tarsi serves as sections of the Order Coleoptera. 
Tergi m, the upper part or back of the abdomen. 
Tessellata, spotted or marked with another colour chequerwise. 
TIIOUAX, the part intermediate to the head and body. (Seep. 31.) 
This part is subject to the greatest variety in shape, sculpture, &c. 
Many of the terms used to distinguish the elytra in Coleoptera are 
also applicable to the thorax. 
Aculcatus, furnished with sharp spines. 
Alqualis, when of the same breadth with the elytra. 
Angulalus, the posterior margin having prominent angles. 
Canaliculatus, with a deep longitudinal groove in the middle. 
Carinatus, the middle part of the disc raised into a straight longitu- 
dinal ridge. 
Convexus, when the surface is elevated like the section of a sphere. 
Cordatus, heart-shaped, the base notched, without angles. 
Crenatus, the margin notched, hut in such a way that the incisures 
are pointed to neither extremity. 
Cristatus, the earinated ridge arched, dentated, and compressed. 
Cucullalm, the earinated ridgehollowed before into a kind of hood. 
Discus, the middle of the thorax, the line from b to c { fig. 4 .pi. HO- 
Gibbus, the disc elevated but not spherical. 
Immarginatus, without clypeus or distinct rim. 
Ineequalis, the surface not flat, but with irregular elevations and de- 
pressions. 
