1905.] Wheeler, The Ants of New Jersey. 2)^7 



fungus gardens are suspended. They consist of a substratum of bits 

 of leaves, buds, green seeds, and caterpillar excrement collected by 

 the ants and woven together by the white hyphas of a mould-like 

 fungus, which is carefully cultivated by the insects and constitutes 

 their only food. Since the culture of the fungus depends on definite 

 degrees of moisture and temperature the ants are very careful of the 

 ventilation of their nest. During the dry spells of midsummer the 

 entrance is closed with bits of leaves and twigs to prevent the escape 

 of the requisite humidity. At such times it is almost impossible to 

 find the nests. In spring, however, when, after the first warm rains, 

 the ants are clearing and renovating their chambers, and again in 

 the fall after they have raised their brood and are preparing for the 

 winter, the external architecture of the nest is more noticeable. The 

 colonies of A. septentrionalis in New Jersey are feebler than those 

 which I have seen near Miami, Florida, and near Austin, Texas. This 

 somewhat depauperate character is evidently the result of unfavor- 

 able conditions at the extreme edge of the range of the species, 

 which can hardly extend further north than the pine barrens. 



Subfamily Dolichoderin^. 

 Dolichoderus Lund. 



43. D. mariae Forel. — Vineland (Mrs. Mary Treat); Manumuskin 

 (Daecke) ; Clementon (Viereck) ; Lakehurst (Davis and Wheeler). 



This ant is one of the most beautiful insects of the pine barrens, 

 where it nests in the pure sand in colonies comprising thousands of 

 individuals. The nests are frequently excavated about the roots 

 of grass {Andropogon sco partus) or turkey-beard (Xerophyllum seti- 

 folium). The workers remove nearly every particle of sand from the 

 roots and dig a pot-shaped cavity from 12-18 inches in depth and 

 3-5 inches in diameter. The spaces between the root-fibers serve as 

 galleries and in them the larvae and pupae are kept. The withdrawal 

 of so much sand from the roots of the grass often destroys the vigor 

 of the plant and prevents it from flowering. Bits of dead leaves, 

 pine-needles, etc., are heaped over the surface between the grass 

 blades, sometimes in sufficient quantity to form a flat mound, but 

 quite as often the top of the nest is concave, owing to the withdrawal 

 of the sand and its being only partially replaced by vegetable debris. 

 The nests are most easily located by first finding the workers on the 

 foliage of the oaks and pines, where they attend plant-lice and mealy- 



