22 Philippine Journal of Science 1919 



The form as above described is very apparently in the fifth 

 instar and about ready for the final molt. 



Mr. McGregor's field notes on Tricentrus fairmairei state that 

 both adults and nymphs are attended by black ants of which 

 he sends specimens. These ants have been determined by Prof. 

 W. M. Wheeler, of Harvard University, as Polijrhachis (Myrm- 

 hopla) dives Smith. I am again indebted to Professor Wheeler 

 for his kindness in making these determinations. 



Tricentrus acuticornis sp. nov. Plate I, figs. 5 and 6. 



Near Tricentrus convergent Walker but differing in size and 

 particularly in the formation of the suprahumeral horns. On 

 superficial examination I had placed these specimens with the 

 males of T. convergent, which they closely resemble in general 

 appearance; but further study shows them to belong to a dis- 

 tinct species. 



Small, dark brown with large white tomentose patches behind 

 each eye, closely punctate, densely pubescent; suprahumeral 

 horns acute, slightly diverging, longer than the distance between 

 their bases, not at all flattened; posterior process straight, ex- 

 tending just beyond internal angles of tegmina; tegmina smoky 

 hyaline ; hind trochanters armed with strong spines. 



Head a little broader than long, subquadrangular, black, the 

 fine punctures almost entirely hidden by the dense silvery pu- 

 bescence; base weakly sinuate, rounded, highest above ocelli; 

 eyes very prominent, gray, extending laterad half as far as the 

 humeral angles; ocelli large, pearly, about equidistant from 

 each other and from the eyes and situated above a line drawn 

 through centers of eyes; inferior margins of gense weakly sin- 

 uate, extending slightly downward from eyes to about middle 

 of clypeus; clypeus longer than wide, densely pubescent, ex- 

 tending for somewhat more than half its length below inferior 

 margins of gense. 



Pronotum black, closely punctate, densely pubescent; meto- 

 pidium perpendicular, broader than high, slightly convex; su- 

 prahumeral horns straight, triquerate, acute, longer than the 

 distance between their bases, extending upward, forward, and 

 slightly outward, tips somewhat recurved ; humeral angles prom- 

 inent, auriculate; dorsum almost straight, sloping downward 

 from suprahumeral horns to posterior process; posterior pro- 

 cess short, acute, sharply carinate above, tip triquerate, sharp, 

 extending just beyond internal angles of tegmina; median ca- 

 rina percurrent, faint on metopidium, strong on posterior 

 process. 



