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. 

 Dichgetae: a group of brachycerous Diptcra 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 Orthoptcra. 



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 behind 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 Coccida; in Lecanium, four knobbed 



hairs. 



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

 pendage 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 (ri 

 Homoptera. 



