43 ALEXANDER PETRUNKEVITCH. 



phantes ovigerus and Lithyphantes oophoms. The detailed de- 

 scriptions of the species will be given later in another place, in my 

 study of Porto Rican spiders. Bathyphanthes is a well-known 

 genus of the family Linyphiidre and has numerous representatives 

 in the United States, Europe and other countries. Lithyphantes 

 belongs to the family Theridiidae and has also a wide distribution. 

 Both are small spiders, B. ovigerus measuring 2.87 mm. in length, 

 L. oophoms 1.628 mm. Of the former species I have collected 

 later several females and a male under similar conditions not 

 far from Rio Piedras, of the Lithyphantes a second female under 

 a cocoanut shell on the beach at Puerto Nuevo Point. Thus I 

 was enabled to make some observations on both species under 

 laboratory conditions. Both behaved much in the same manner. 



The cocoon of B. ovigerus is globular and rather large in pro- 

 portion to the size of the spider, being fully 2 mm. in diameter, 

 with thin, white walls and a few eggs well visible through the 

 silk. The spider makes no web of any kind, but walks dragging 

 the cocoon behind her and if disturbed runs for shelter. Deprived 

 of the cocoon the spider shows signs of uneasiness and on dis- 

 covering the cocoon grasps it with her chelicerae, bends her 

 almost globular abdomen until the spinnerets reach the cocoon 

 from below, releases her hold on it with the chelicerae and starts 

 off dragging now the cocoon behind her. For two days she 

 behaved this way. On the third day I was surprised to find her 

 sitting on the bottom of the jar while the cocoon was hanging 

 close by, suspended by a few threads in a small web made of 

 loose threads and much of the type common in small Linyphiids. 

 The explanation of the change in behavior was furnished the 

 same day when minute spiderlings emerged from the cocoon. 

 Toward the end, then, of her maternal duties the original instinct 

 common to all Linyphiids asserted itself, showing that the species 

 still retains some of the family habits and that the new habit did 

 not develop to the point characteristic for Lycosids, where the 

 spiderlings are carried by the mother on her back until they have 

 moulted and are large enough to shift for themselves. 



Lithyphantes oophoms has an elongated abdomen vividly 

 marked with black and white, the colors forming a pattern of a 

 type more or less common for the genus. The cocoon is globular, 



