74 POMONA JOURNAL OF ENTOMOLOGY 



Tribe Lacnidi (Lachnides) 



I. Tarsi with the first article much elongate, always subequal to half of the 



second article. 

 A. Apterous and winged females with antennae formed always of five 

 articles. 



Genus Bssigella Del Guercio. 

 (Sp. top. Lachmts calif ornicus Essig.) 

 AA. Apterous and winged females with antennae of six articles. 



Genus Eiilachiiiis Del Guercio. 



II. Tarsi with the first article very short, always shorter than half of the second 



article. 



Genus Lachnus Burm. 

 Among other characters of interest in the systematic study of the species, 

 it is enough to mention that the apterous and winged females have shorter 

 antennae, with the third article equal to the two following together, the two 

 last subequal — including in the fifth article its very short appendix. It lives 

 on a cultivated pine at Claremont. California, where it is common, according to 

 Essig. 



III. Pemphigus radicicola Essig 



The apterous and winged females in this species have the abdomen dis- 

 tinctly margined. Their antennae are formed of five articles. In the apterous 

 female the second article is rounded at tip where it is broader than at base and 

 is as long as the third article, longer than the fourth, and a little shorter than 

 the fifth. In the winged female the second article is also somewhat swollen 

 at the tip, but is subequal to only half of the third, the third becoming attenu- 

 ated in the apical half, while the fourth is clavate like the fifth, but shorter 

 than it. The third article is provided with numerous sensoria of various sizes. 

 Now, even from these characters alone it seems evident to me that this species 

 is not a Pciiifyhigus, and also that because of the wing venation it forms a part 

 of the Pentafidi. In the fore wings it has the four oblique veins of Pcntaphis, 

 but in that genus the two oblique veins of the posterior wings are distant or 

 remote, while in this they spring from practically the same point. Pemphigus 

 radicicola resembles Pentaphis, as the genus Pachypappa resembles the genus 

 Schizoneura, or as the genus Pemphigus resembles Tetrancura. It, therefore, 

 can well serve for the type of a new genus, which, because of the peculiar posi- 

 tion of the two oblique veins of the posterior wings taken in comiection with 

 the distal portion of the subcostal, may well be named Trifidaphis. The genera 

 in question may be separated thus : 



Tribe Pentafidi ( Pentaphides) 



A. Posterior wings with the two oblique veins distinct and remote. 



Genus Pentaphis. 

 (Sp. tip. Tychea triinalis Pass.) 



