USED IN ENTOMOLOGY. 37 



Deutocerebral segment: =;antennal segment; q. v. 



Deutocerebrum: the middle portion of the brain, formed by the ganglion of 



the 2d primary segment ; also termed antennal or olfactory lobes from the 



parts it innervates. 

 Deutoplasm: the yolk or food plasm of an ovum. 

 Deutotergite: the secondary dorsal segment of the abdomen. 

 Dextrad: extending or directed toward the right. 

 Dextral: to the right of the median line. 



Dextro-caudad: extends obliquely between dextrad and caudad. 

 Dextro-cephalad: extends obliquely between dextrad and cephalad. 

 Di: as a prefix, = two. 

 Diaphanous: semi-transparent: clear. 

 Diaphragm: any thin dividing membrane; that thin membrane separating 



the cavity containing the heart from the rest of the body. 

 Diarthrosis: any articulation that permits of motion. 

 Diastole: that regular expansion of the heart that draws the blood inward: 



see systole. 

 Dichaetae: a group of brachycerous Diptera with a proboscis consisting of two 



parts : Muscids, etc. 

 Dichoptic: Diptera; eyes separated by front: not contiguous: see holoptic. 

 Dichotomous: forked: dividing by pairs. 

 Dichromatism: the possession of two color varieties. 

 Dictyoptera: an ordinal term applied to the roaches: also more generally, 



to the Orthoptera. 

 Didactyle -us: two-toed: with two tarsi of equal length. 

 Didymus: double: geminate. 



Difformis: irregular in form or outline: not comparable; anomalous. 

 Diffracted: bending in different directions. 

 Diffuse: spreading out; without distinct edge or margin. 



Digestive tract: the alimentary canal as a whole: more specifically that por- 

 tion l)ehind the crop, in which assimilation takes place. 

 Digitate: finger-like, or divided into finger-like processes. 

 Digitiform: formed, shaped like or having the function of a finger. 

 Digitules: appendages on the feet of Coccidcc ; in Lccaninm, four knobbed 



hairs. 

 Digitus: the terminal joint of the tarsus, bearing the claws: a small appendage 



attached to the lacinia of the maxilla ; rarely present and probably tactile. 

 Digoneutism: the power to produce two broods in one season. 

 Dilatatus: Coleoptera ; a margin, when the sharp marginal edge extends 



beyond its usual limit : the base when the transverse diameter is much longer 



at one part. 

 Dilated: widened, expanded. 

 Dilation: an expansion or widening. 



Dilute: thinned out: applied to color means weak or pale. 

 Dilutior: much thinned out or diluted. 

 Dimera: forms with two-jointed tarsi: specifically applied to some groups of 



J-lo)]ioptcra. 



