GLOSSARY OF TERMS USED IN ENTOMOLOGY 335 



Melanism. An abnormal darkening. 



Mellifera. Honey-makers. 



Mbntum. a labial sclerite bearing the movable parts. 



Mesenteron. The middle portion of the primitive intestinal canal ; 

 the midgut. 



Meso-. Middle. 



Mesonotum. The primitively upper surface of the middle thoracic 

 ring. 



Meta-. Posterior. 



Metabolism. Transformation, changes of food into tissue and of 

 tissue into waste products. 



Metanotum. The primitively upper sm'face of the third or posterior 

 thoracic ring. 



Metathorax. The third thoracic ring or segment. 



Metopidium. The anterior declivous sm-face of prothorax in Mem- 

 bracidae. 



MiCROCH^T^. Small bristles, as opposed to macrochsetse, in Diptera. 



Micron. The unit of microscopic measurement. 



Mimetic. Mimicry of appearance but not structure. 



Mimicry. The resemblance of one animal to another not closely 

 related. 



Monoecious. The combining of both sexual elements in one indi- 

 vidual. 



Moult. The transformation of a larva from one instar to another; 

 the cast skin of a larva that has moulted. 



Nearctic. Temperate and arctic North America, including Green- 

 land. 



Necrophagous. Living in or on carrion. 



Nectaries. Honey-tubes. 



Neotropical. That part of the earth's surface embraced in the 

 greater part of Mexico, West Indies and South America. 



Nocturnal. Night-flying. 



Obsolete. Indistinct, nearly or entirely lost. 



Obtect. Wrapped in a hard covering. 



( )btected. Covered with a chitinous case which conceals appendages 

 but through which their outlines are revealed. 



(Ocelli. Plural of ocellus. 



Ocellus. A simple eye. 



Ontogeny. The development of the individual as distinguished from 

 that of the species. 



Ootheca. The covering of an egg mass. 



Operculum. A lid. 



Optic. Relating to the organs of vision. 



Oral. Pertaining to the mouth. 



Oriental. In geographical zoology as used by Wallace, that part of 

 the earth's surface including Asia east of the Indus River, south of the 

 Himalayas and the Yangtse-kiang watershed, Ceylon, Sumatra, Java, 

 and the Philippines. 



Ova. Eggs. 



