NO. 1580. NE W SPECIES OF CALIGIN.E— WILSON. 607 



PARAPETALUS OCCIDENTALIS, new species. 

 Plate LTII. 



Types.— Cat. No. 32808, U. S. National Museum. 



Female. — Carapace one-third the entire length, ovate, consider- 

 ably wider than long, and quite squarely truncated posteriorly. 

 Frontal plates A\dde and prominent, with a slight incision at the cen- 

 ter; lunules medium sized, widely separated, and projecting half 

 their i.iameter. Posterior sinuses broad and shallow, the median 

 lobe aJ^ .ost exactly one-third the entire width and not projecting 

 behind the lateral lobes. The latter are squarely truncated poste- 

 riorly and slightly curved inward. Thoracic area less than one- 

 fourth the entire length and semicircular in outline. Eyes small 

 and fused on the mid line. 



Fourth (free) segment two-fifths as wide as the carapace, and nar- 

 rowed anteriorly where it joins the latter. It is entirely without 

 dorsal plates, processes, or appendages except the fourth legs. Geni- 

 tal segment orbicular and only live-sixths as long as wide, while it 

 is three-quarters the width of the carapace. It is produced on its 

 ventral surface into two large membranous wdngs, wliich project 

 well beyond the lateral margin on either side and curl up dorsally 

 at the edges. 



Each wing is considerably thickened at its base, where it also pro- 

 jects in front of the genital segment and comes up against the side 

 of the fourth segment; but it thins rapidly and becomes very delicate 

 and pliable toward the margins. Each wing, furthermore, is pro- 

 longed posteriorly into a well-rounded lobe, which reaches backward 

 nearly to the posterior end of the abdomen. Between the bases of 

 these large lobes the genital segment itself is prolonged backward 

 into very much smaller, flattened lobes, wliich lie side by side at the 

 median line under the bases of the egg strings. In young females 

 the two are entirely separate, but later they often fuse into a single 

 semicircular and laminate flap or lobe. 



The abdomen is half as long again as the genital segment, and its 

 dorsal surface for the entire length on either side is produced into a 

 membraneous wing which extends out a little beyond the lateral mar- 

 gin of the genital segment and then curls over ventrally around the 

 egg strings. These two wings also project posteriorly a little beyond 

 the tips of the anal laminae. 



On the posterior margin there is ({uite a deep incision at the middle 

 for the anus. The anal lamana^ stand close to this incision, are of 

 medium size, somewhat enlarged at the tip, and terminate in four 

 short sette of about the same length. 



The egg strings are wide, a little longer than the coml)ined genital 

 segment and abdomen, and each contains 60 or 70 eggs. 

 Proc. N. M. vol. xxxiii— 07 39 



