28 THE COCCIDAE 



identified, particularly in the early nymphal stages. The con- 

 stricted part of the cuticle, the coria, is usually flexible and marks 

 the division between adjacent segments. The coriae are named 

 from the segments forming their caudal boundary, as the one 

 cephalad of the prothorax is the procoria, the one cephalad of the 

 mesothorax is the mesocoria, the one cephalad of the first abdominal 

 segment is the unacoria, etc. 



The segmentation of the body of the adult coccid is greatly 

 obscured through the obliteration of the coriae by the expansion of 

 the body to hold the ovaries or because of its covering of wax or 

 probably in most cases to both of these causes. In the first nymphal 

 stage of certain species the segments and coriae can generally be 

 identified, but they gradually disappear with each successive molt. 

 The microthorax can not be identified and the microcoria, micro- 

 thorax, and procoria are represented by a single continuous 

 transverse area, which is separated from the head by an infolded 

 area which has been designated the procoria. Where the thoracic 

 coriae are wanting, the thoracic region can be identified from the 

 attachment of the legs when these are present. But where the 

 coriae are obscure or wanting and the legs are wanting, the extent 

 of the thoracic segments can be approximated only by the attach- 

 ment of the mouth-parts and the location of the thoracic spiracles, 

 the mesospiracles and the metaspiracles. 



Head. The head is an area of considerable extent on both 

 dorsal and ventral aspects. It typically bears a pair of antennae, 

 a pair of simple eyes, a rostrum or labium, and a pair of bristle- 

 like mandibles, and a pair of bristle-like maxillae. These are 

 usually all present in the first nymphal stage even though all or a 

 part of them are wanting in all the later nymphal stages and the 

 adult. The caudal extent of the head is marked by the procoria, 

 but this is wanting in many adults, as Diaspidinae and Lecaniinae, 

 where the head and three thoracic segments form a continuous 

 undivided area. This fused area is designated by some writers as 

 the cephalothorax. Something as to the size and shape of the 

 head can frequently be determined from the appendages which 

 it bears and their attachment. The head is generally figured and 

 described as being triangular in outline and limited for the most 

 part to the ventral aspect. Its true size and shape are more 

 easily determined in nymphs of the first stage. The subtriangular 

 ventral area frequently described as the head is only a part of it 

 and represents the fused front and clypeus. It is designated as 

 the frons in the Homoptera and this name should be used here. 



