THE COCCIDAE OF SOUTHWESTERN UNITED STATES 



11 



Genus ICERYA Sign. 

 Fig. 3. 



Ordinarily but little attention seems to have been paid to morpho- 

 logical characters (other than the antennae and legs) in describing spe- 

 cies of this genus. A study of the material available, representing five 

 species, indicates that these species, at least, can quite easily be separated 

 by morphological characters. 



These characters are to be found in the spines and setae and the 

 various pores. The shape and size of the setae and their arrangement, 

 whether in tufts or singly, are very useful. In /. purchase, for example, 

 the setae are very abundant, all slender and in part arranged in conspicu- 

 ous tufts. In 7. rileyi the setae are few and are not arranged in tufts. 



Fig. 3. Icerya, morphological details : A, diagram of ventral side of female to 

 show position of ring of pores from which the ovisac is excreted ; B, por- 

 tion of ventral pore ring of /. rileyi; C, portion of ventral pore ring of / 

 purchasi; D, types of dermal pores. 



Two types of pores are found in the genus (Fig. 3D). These are 

 very similar in appearance, but those of one type are nearly twice as 

 large as those of the other. The relative numbers of these two types are 

 of value, /. rileyi having all the pores of the smaller type, while in 7. sey- 

 chellarum there are many of the larger type as well. The arrangement 

 of the pores by which the ovisac is secreted is especially significant. 

 These pores are disposed in a large ring on the venter of the abdomen 

 (Fig. 3A), this ring enclosing an area in which pores and spines are 

 practically lacking. In 7. rileyi (Fig. 3B) the pores are very numerous 

 and are associated with a nearly equal number of short spines. In 7. 



