290 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



I have seen only three specimens of Macrogomphus: One of these 

 is a male of guadratus collected by Doctor Abbott on Big Tambelan 

 Island, China Sea, August, 1899. The other two are females of a 

 form which I am unfortunately unable to refer to an}^ described 

 species and which I hesitate to name from the single sex, though 

 the specimens show many characters which might justify this. (See 

 figs. 14, 15, 16.) 



6. MACROGOMPHUS SPECIES (parallelogramma group). 



Abdomen without a])pendages 45 nun.; liind wing 37-3.S mm. 

 Antenodals, front wing 17-18; hind wing 12-14; postnodals, front 

 wing 12; hind wing 3 0-12. Cubital space in front wing witli 2 

 additional cross veins. Five cross veins between M^..^ and j\T^ in 

 front wang and 3 in hind wing; basal antenodal second series present. 

 Abdominal segments 7-10 measuring; 7, 5 mm.; 8, 3.5 mm.; 9, 6 to 

 6.5 mm.; 10, 1 mm. 



Rear of head and lower lip pale dull yellow, darker above behind 

 the eyes; face in front obscure bro^vn without markings, shading 

 continuousl}^ from the frons into paler below, so that the upper lip 

 at its lower edge passes into the color of the lower lip; frons above 

 entirely greenish yellow; vertex black, dull yellow at the base of the 

 occipital plate; occipital plate dark brown, produced in the middle 

 in a two-pointed tubercle. 



Thorax black, the yellow dorsal stripes almost parallel, beginning 

 just before the antealar sinus and widened below to form a meso- 

 thoracic half collar, interrupted at the middle. A long yellow stripe, 

 gradually widening below, on the mesepimeron; a similar but wider 

 stripe on the metepimeron; the black area between tlie stripes with 

 a superior yellow s]:)ot, which may be greatly reduced or may extend 

 downward half the length of the spot on the metepimeron. Legs 

 brown, wdthout distinct markings; tibise and apices of femora black. 



First 3 abdominal segments obscurely colored, dorsum of 2 and 3 

 with a median dorsal stripe, wide on the basal half of 3, reduced to a 

 line on the apical half; 4-7 basally annulate with yellow, scarcely 

 one- third of each segment on 4-6, fully one-half on 7; 8 black; 9 

 with a small obscure l)asal lateral spot; 10 ]>ale obscure yellow. 



Described from two females, Trong, Lower Siam, Dr. W. L. Abbott, 

 collection U. S. National ^Museum. The head of one s]:>ecimen is lost. 



This species is separated at once from rohustus by the color of the 

 head. From annulatus it is separated l^y several characters: Color 

 of head, legs, and abdomen. From nlbardse by color of head and 

 abdomen, and form of occiput. From paralldogramma by color of 

 head and abdomen and form of occiput. From montanus by color 



