52 A CONTRIBUTION TO THE KNOWLEDGE OF 



Material examined. From Holacantha emoryi, near the Hassayampa 

 River, west of Phoenix, and from Koeberlinia spinosa, between Bowie 

 and San Simon, Ariz. 



Scale. Of the type common to the genus. 



Female. Derm membranous throughout except for the pygidium. 

 Abdominal segments projecting but little at the margins and without 

 marginal gland spines but with many small tubular ducts. Each abdom- 

 inal segment dorsally with a submedian group of ducts on each side. 

 Median lobes large, their mesal margins diverging rapidly, their tips 

 rounded, sometimes slightly crenulate. Second and third pairs of lobes 

 extremely small. Between the first and second pair is a single low gland 

 prominence ; between the second and third another. Beyond the third 

 pair are many small gland spines arranged in clusters of three to five 

 spines. Marginal ducts somewhat larger than those of the dorsum, their 

 pores surrounded by a narrow chitinous rim. Dorsal ducts extremely 

 numerous. Their arrangement may best be gathered from the figure. 

 Five groups of circumgenital pores present, each group with many pores. 



Notes: In the specimens from Koeberlinia the second and third pairs of 

 lobes are noticeably larger than in those from Holacantha, but there appear to be 

 no other differences. 



Genus PSEUDODIASPIS Ckll. 



This genus appears never to have been definitely described, its author 

 having merely stated that : "Pseudodiaspis will, however, no doubt event- 

 ually be regarded as a distinct genus, on account of the mytiliform male 

 scale and other characters." 



Through the kindness of Professor Cockerell I have been enabled 

 to see a slide of P. larreae Ckll., the type of the genus. Unfortunately 

 this slide is not in such condition as to permit the redescription of the 

 species or even any very definite conclusions as to its character. The 

 species does appear, however, to be of the Diaspis type rather than of the 

 Aspidiotus type, the tubular ducts at the margin being of the character 

 found in the former genus. 



I am here utilizing this generic name to designate a group of species 

 belonging to the Diaspis series, but agreeing in the absence of circum- 

 genital pores and in having the scale of the male somewhat elongate, in 

 texture resembling that of the female, with the exuviae near one end. 

 That these species are congeneric with P. larreae or even with each other 

 is perhaps questionable, but this seems to be the only genus available for 

 them at present. One of them has been referred to Targionia, a genus 

 that, if I may judge from the species available to me for study and from 

 the literature, is purely artificial and of a most heterogeneous character, 



