178 



jTirst annual 



backwards) : A doul)le row of four pairs of spines extends back 

 through the medial section of the dorsum as far as back edge of 

 coxa three. Beginning over the front edge of coxa two, a sub- 

 marginal row of three, and a marginal row of three, extend back 

 as far as hack edge of coxa three. The longest pair of spines in the 

 dorsum are situated behind and equally distant from the terminal 

 spines of the medial and sub-marginal rows of their respective sides. 

 Around the posterior end of the abdomen on dorsal and ventral sides 

 are scattering, fine, short spines. Peritreme long and only slightly 

 bent around coxa two and extending forward past coxa one. Anal 

 plate separate in both sexes, large, broad, and not pointed behind but 



Figure 96. Seius orchestoideae 



with the posterior margin straight across; all corners rounded. Anal 

 opening in the center. Male genital opening on anterior margin of 

 sternal plate ; no teeth on the legs. 



From the foregoing characters this species according to Banks's 

 key belongs in the genus Seius, which however he says has been 

 divided by Ribaga into four sub-genera. As I have not been able 

 to obtain Ribaga 's paper, it seems best to place my specimens pro- 

 visionally in the genus Seius sens. lat. This species was taken from 

 the large aniphipod On licsinlilcn <-<ilifi>riii<ti/<t, which is common on 

 the beach. The mites were fastened underneath the body and as 

 many as twenty-seven were taken from one aniphipod, and great 



