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 

 separate 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 caecal tubes or pouches : any exten- 

 sions or evaginations of the hypodermis. 



Dividens (vena): Orthoptera; 1st anal (Comst.). 



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

 low the antennae (Cocker ell). 



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 

 individuals and in which differentiation is yet active. 



Dorsad: extending or directed toward the upper side. 



Dorsal: of or belonging to the upper surface; in Diptcra, 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 pygidiutn, 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 Diaspina 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: Diptcra; 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: Diptcra; 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 occu- 

 pied 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: Diptcra; the lateral suture between dorsum and pleu- 



