USED IN ENTOMOLOGY. 99 



Penicilli: a pair of small style or cerci-like pieces on the tip of the 8th dorsal 



segment of abdomen of various male Hymenoptera. 

 Penicilliform: pencil-like or shaped. 

 Penicillum: a pencil or brush of long hair attached at the end of a stalk as 



long as the brush, and folded in a lateral groove in some male moths. 

 Penis: the flexible, membranous, intromittent organ of the male. 

 Pennaceous: = pennate. 



Pennate: feathered or bearing feather-like processes. 

 Penniform: feather-like in form. 



Pentagon -urn: a five-sided figure with five equal or unequal angles. 

 Pentamera: Coleoptera with 5-jointed tarsi. 

 Pentamerous: species having five-jointed tarsi. 

 Penultimate: next to the last. 

 Peptone: a soluble proteid compound produced by the digestion of albu- 



mcnoid food substances. 

 Per-: as a prefix, means very; extremely; through. 

 Percipient: with the power of perceiving. 

 Percurrent: running through the entire length. 

 Pereion: the prothorax. 

 Pereipoda: the second and third pair of thoracic legs of larvae, and the 2d pair 



in adults. 

 Perfoliate: divided into leaf-like plates: applied to antenna; with disc-like 



expansions connected by a stalk passing nearly through their centres : also 



to any part possessing a well-developed leaf-like or plate-like expansion. 

 Pergamenous: thin, partly transparent; resembling parchment. 

 Peri-: round about. 

 Periopticon: a complex nerve structure back of the basilar membrane of the 



eye. 

 Pericardial: around, or belonging to the heart. 

 Pericardial cavity: the space between the diaphragm and dorsal body wall, 



which contains the heart. 

 Pericardial cells: specialized cells, which lie along both sides of the heart, and 



whose function it is to purify the blood. 

 Pericardial chamber: is the open space around the heart or dorsal vessel. 

 Pericardial diaphragm: a delicate membranous tissue attached to the ventral 



surface of the heart and laterally to the body wall: = dorsal diaphragm; 



wings of the heart. 

 Peri-intestinal: that part of the body cavity around the alimentary canal. 

 Peri-neural: situated around a nerve: the body cavity immediately surround- 

 ing the nervous system. 

 Periodical: recurring at regular intervals. 



Periopticon: third ganglionic swelling of optic tract: see opticon. 

 Peripheral: referring to the outer margin. 

 Peripheria: the entire outline of the body. 

 Periphery: the circumference or outer margin. 

 Peripneustic: larvae which have the spiracles absent on middle and posterior 



thoracic rings, and present on all other body segments. 



