40 EXPLANATION OF TERMS 



Divergent: spreading out from a common base; in Coleoptera, tarsal claws 

 are divergent when they spread out only a little : divaricate when they sepa- 

 rate widely. 

 Diverse: unequal: differing in size or shape: of various kinds. 

 Diverticulum -la: an off-shoot from a vessel or from the alimentary canal: 

 usually blind or sac-like : applied to the cecal tubes or pouches : any exten- 

 sions or evaginations of the hypodermis. 

 Dividens (vena): Orthoptera; ist anal (Comst.). 

 Dog-ear marks: in bees: small, subtriangular marks of light color, just below 



the antennas (Cockerell). 

 Dolabriform: hatchet-shaped: compressed, with a prominent dilated keel and 



cylindrical base. 

 Dolioloides: applied to obtect or coarctate pupae. 



Dominant: a character more constant and conspicuous than any other: a type 

 or series occurring in large numbers both as to genera, species and indi- 

 viduals and in which differentiation is yet active. 

 Dorsad: extending or directed toward the upper side. 

 Dorsal: of or belonging to the upper surface; in Diptera, that face of the 



laterally extended legs visible from above. 

 Dorsal bristles: see dorso-central. 

 Dorsal diaphragm: the wings of the heart, or the very thin membrane upon 



which these muscles rest : = pericardial diaphragm, q. v. 

 Dorsal gland orifices: in Diaspince, oval orifices arranged in more or less 

 distinct rows on the surface of the pygidium, through which is discharged 

 the material of which the dorsal scale is formed. 

 Dorsal glands : see last preceding title. 

 Dorsal line: in caterpillars, extends longitudinally on the middle of the back 



or dorsum. 

 Dorsal scale: that part of the covering scale of the Diaspince that lies above the 



insect, as opposed to the ventral scale, which lies below. 

 Dorsal space: in slug-caterpillars is the area between the sub-dorsal ridges. 

 Dorsal vessel: the heart; q. v. 

 Dorsi-meson: the middle of the upper surface. 



Dorso-alar region: Diptera; between the transverse suture and the scutellum 

 on one side and the root of the wing and the dorso-central region on the 

 other. 

 Dorso-central bristles: Diptera; two or four longitudinal rows on the inner 



part of the dorsum. 

 Dorso-central region: Diptera: bounded by two imaginary lines drawn from 

 the scutellar bridges forward, and coinciding with a space free from bristles 

 that exists on the outer side of the dorsal rows and is often occupied by a 

 dorsal thoracic stripe. 

 Dorso-humeral region: Diptera; bounded by the anterior end of thorax and 

 transverse suture on two sides and by the dorso-pleural suture and dorso- 

 central region on the two others. 

 Dorsolum: the mesoscutum. 

 Dorso-pleural suture: Diptera; the lateral suture between dorsum and pleu- 



