158 Zoology of Colorado 



Drury received some of the finest North American dragon-flies, 

 at that time entirely new to science. So we find at Boulder 

 Plathemis lydia of Drury, in the male of which the wings are very 

 broadly dark reddish brown in the middle, but clear at either end, 

 except for an elongate basal stripe, in which is a small more or 

 less transparent central area. Then we have from Florissant 

 (taken by Mr. S. A. Rohwer) Drury 's Libellula pulchella, each 

 wing with three dark brown patches, one at the base, one in the 

 middle, one at the tip, while between them are chalky clouds. 

 The white clouds may be absent in the female. The female of 

 Plathemis lydia is smaller than that of L. pulchella, the hind wing 

 about 33 mm. long (over 40 in L. pulchella), but the wing mark- 

 ings are almost as in L. pulchella. The median dark patch of 

 P. lydia sends a pointed projection from its inner side, and as 

 there is another process near the upper margin on the outer side, 

 the whole patch has rather the outline of the head of some wood- 

 pecker. The genera Plathemis and Libellula are in fact extremely 

 closely allied, and according to a recent ( 1 922) revision by Kennedy, 

 Plathemis is to be regarded as a subgenus of Libellula, instead of 

 a full genus. For species of the type of L. pulchella he proposes 

 a subgenus Neotetrum. A second species of Neotetrum is L. foren- 

 sis of Hagen, in which the ends of the wings are clear. According 

 to Kennedy, L. forensis will breed in alkali ponds, but L. pulchella 

 breeds only in strictly fresh water. A specimen of L. forensis 

 was taken by Mr. F. W. Rohwer at Boulder. It not only lacks 

 the dark tips to the wings, but the median patch is enlarged and 

 irregularly dumb-bell shaped. 



There are still other species of Libellula in Colorado. The 

 L. quadrimaculata of Linnaeus, which is not uncommon, has the 

 wings clear except for an orange suffused area at the base, bounded 

 below by black on the hind wings, a small spot at the nodus, and 

 the long dark pterostigma near the end of the wing. The black 

 area at the base of the hind wing has a triangular expansion, on 

 which the veins appear white. This species, found in the Old 

 World from England to Japan, is not related to any other American 

 form, and is surmised to be a comparatively recent immigrant 

 from Asia. Another Libellula, taken at Pueblo by Mr. Glenn 

 Hite, and kindly determined by Dr. Calvert, is the L. saturata of 

 Uhler. It is large, the hind wing about 40 mm. long; the body is 



