38 SMITHSONIAN" MISCELLANEOUS COLLECTIONS VOL. 89 



AETHEANDRA MULTIPLEX, n. sp. 



Plate 2, figs. 4 and 5 



Three males, four females, and four young were collected in the 

 heavy forest near the top of the ridge back of Kings Bay, Tobago, 

 February 20, 1932. They were found among very moist, decaying 

 sheaths and leaves from a huge cabbage palm, and on being disturbed 

 ran rapidly for shelter. 



Description. — The living color was bright light brick-red and the 

 thickened hairs were quite apparent in spite of the rather small size 

 of the animals. The largest specimen was 9 mm long and 1.5 mm 

 broad. Structural characters have been sufficiently set forth in the 

 generic description. 



This is a very remarkable milliped in several particulars. The fe- 

 males are not strikingly different from many other small polydesmids, 

 but the males differ from them so much that had the sexes been col- 

 lected separately they would have been considered as distinct species, 

 or even as representing different genera, for the secondary sexual 

 modifications of the male not only greatly affect the anterior legs and 

 sterna, but the shape of the head and anterior segments is changed 

 in a very unusual manner. Outstanding differences of the head and 

 dorsum are not expected between male and female in the Polydes- 

 midae, but this species is exceptional in these particulars, for the head 

 and first four segments are very dissimilar in the sexes. Although it 

 is usually found that some of the legs in advance of the gonopods 

 differ from the corresponding female legs in this family, the modifica- 

 tions seldom are as extreme or numerous as those of the second and 

 third male legs of A. multiplex, and the sternum between the latter 

 legs is remarkably developed. In view of the many secondary modi- 

 fications it is surprising not to find complex gonopods as a corollary, 

 but instead they are of a simplicity not paralleled in any other member 

 of the family and probably not even surpassed within the order 

 Merocheta. 



Type.— U.S. 'NM. no. 1099. 



AGENODESMUS, n. gen. 



Type. — Agenodesmits reticulatus, n. sp. 



Diagnosis.- — -The general appearance of the animal is that of a small 

 polydesmid, and although the dorsum lacks tubercles or broad, convex 

 areas, the setae are rather typical. The shape of the first and last seg- 

 ment and of the lateral carinae, the dorsally placed pores, and the 

 structure of the gonopods are definitely suggestive of the smaller Poly- 



