GLOSSARY OF TERMS USED IN ENTOMOLOGY :537 



Pygidium. The last dorsal segment left exposed by the elytra. 

 Pygofer. The last segment of the abdomen in certain Homoptera, 

 ^'specially the lateral margins which appear in ventral view. 



Radial. Pertaining to the radius or radial vein. 

 Rostrum. A snout-like i)rolongation of the head. 



ScABER. Rough, uneven. 



Scape. The second articulation of the antenna^, often elongateil. 



Scutum. The second dorsal sclerite of the meso- and metathorax. 



Sensoria. The circular openings covered by membrane on the 

 antennae or legs of plant lice. 



Serrate. Like the teeth of a common saw. 



Sessile. Closely attached. 



Setaceous. Bristle-shaped, slender, tapering. 



Social. Living in communities. 



Spermatogenesis. Development of the spermatozoa. 



Spinneret. Any organ consisting of an internal tube, terminating 

 in a pore, spine or process, producing a silky or waxy fiber. 



Spiracle. A breathing pore opening to the trachea. 



Stage. A period in the course of development. 



Stellate. Star-shaped. 



Sterile. Incapable of reproduction. 



Sternite. The ventral piece in a ring or segment. 



Subimago. The stage in ephemerids and some other insects just 

 after emergence from the pupa and before the final moult during flight. 



Tenent hair. Specialized hair adapted for clinging or clasping. 



Teneral. That state of the imago just after its exclusion from pupa 

 or nymph, in which neither coloring nor clothing is fully developed. 



Teres, terete. Cylindrical. 



Tergal. Belonging to the primitively upper surface. 



Thorax. The second or middle portion of the insect body, bearing 

 the true legs and wings; made up of three sections, the pro-, meso- 

 and metathorax. 



Trachea — .e. The breathing tubes of insects. 



Tracheate. Supplied with a trachea. 



Tracheoles. The capillary trachea of the adult as they develop 

 in masses in the larva; very small, slender tracheae. 



Transition zone. The transcontinental belt in which the austral 

 and boreal elements overlap; it is divided into a humid or Alleghanian- 

 area, a western arid area, and a Pacific coast humid area. 



Trochantine. The basal part of the trochanter when it is two- 

 jointed. 



Tumid. Swollen. 



Tylus. The anterior central lobe of the head in Hemiptera. 



Unicolorous. Of one color throughout. 



\'aginate. Inclosed in a bivalved sheath. 



\'alve or \'AL^■UL.E. The expanded plate-like galea of the maxilla in 

 many Hymenoptera. 



