no. 2089. NOTES ON NEOTROPICAL DRAGONFLIES— WILLIAMSON. 609 



little village, flanking the Government road over which we traveled by 

 mule in 1905.) The collection also contains a male and female of P. 

 nathalia Selys, taken at Gualan, Department Zacapa, the male on 

 June 13, the female June 16, 1909. No Palaemnemas were taken by 

 me in Guatemala in 1905, and the number of specimens known from 

 other sources has been very limited. It was therefore deemed desira- 

 ble to study this material carefully, with the view of determining the 

 variability of certain characters, and especially to describe the female 

 of paulina which has not hitherto been known. 



I do not recall the circumstances under which the P. nathalia at 

 Gualan were taken. I collected at widely separated localities on 

 June 13 and 16, but there is no doubt, I think, that the male and 

 female taken belong to the same species. 



On the other hand I have a vivid recollection of the locality where 

 P. paulina was found at El Fiscal. For some time prior to June 5, on 

 which date there was a heavy rain in the afternoon at El Fiscal, there 

 had been a continued and severe drought. Within a week after the 

 first rain of June 5 the country had greened up beautifully. In the 

 last stages of the drought all the water used by the Indian family with 

 whom we lived at El Fiscal was carried from a small stream (called a 

 river) flowing in a deep ravine about 1 mile or more north of the vil- 

 lage. In places the sides of this ravine were perpendicular or even 

 overhanging. Several times a large and extremely rapidly flying 

 swift was seen here and parrots were often very numerous about 

 holes in certain perpendicular dirt faces. At places the sides rose less 

 abruptly and agaves were very numerous. At several points there 

 were boggy spots on the sides of the ravine, about which grew some 

 of the arums with other lush vegetation. Hetaerina capitalis was com- 

 mon in this ravine. The Palaemnemas occurred especially about the 

 boggy spots, resting on larger leaved plants near the ground, and fly- 

 ing low and through brush to escape. One of the males, taken June 3, 

 has a small fly in its mouth. The fly is a muscid, apparently one of 

 the pomace flies. 



In addition to the several characters mentioned below in which 

 these two species differ, nathalia and paulina of both sexes may be at 

 once separated by the form of the posterior ridge or keel of the occiput 

 as seen in a direct dorsal view of the head. This ridge is equal in 

 length to the distance between the antennae, and directly posterior to 

 each antenna is a distinct prominence on either end of this ridge or 

 keel. In paulina the ridge is cut abruptly away externally at either 

 end, leaving the prominence with a very distinct angle of about 90° ; 

 in nathalia, on the other hand, these prominences are low, symmetri- 

 cal and rounded. I regret that I can not study this character in other 

 species. It has not been mentioned in descriptions but its diagnostic 

 value in the case of paulina and nathalia can not be overlooked. 



In colors nathalia is a very much duller insect than paulina. 

 59758°— Proc.N.M. vol. 48—14 39 



