PAMPIIILIDI: ATKYTONE ZABULON. 1623 



a few threads from rib to rib, and places itself beliind tiie threads" (Saun- 

 ders). This latter action is performed by carrying a thread repeatedly 

 between the same points, each thread being drawn tightly and made a 

 little shorter than the previous, until the edges are brought so near to- 

 gether that the caterpillar has oidy room to withdraw its head ; similar 

 bands are made at short intervals ; the process is very slow and is carried 

 on without cessation until completed ; one of the little strands is composed 

 of twenty or thirty threads. If at all disturbed, it at once makes a new 

 nest, which, as it is always very slight, is no very ditHcult task ; it is ex- 

 tremely deliberate in all its movements, remains quietly in its nest by 

 day and ranges the neighborhood for food at night ; wlien about to change 

 its skin it forsakes its nest and crawling downward conceals itself, generally 

 head downward, among the roots and stems of the plants ; it also inva- 

 riably leaves its nest to expel its excrement, being very cleanly in its 

 habits like most other Hesperidae, in marked contrast to the caterpillars of 

 some of the higher buttei-tlies. 



Pupation. "When about to change to chrysalis, the caterpillar con- 

 structs a nest of growing grass blades, generally near the joints, similar 

 to its former habitation ; continuing its work, however, it closes up all 

 the interstices and even the upj)er extremity of the nest (which previously, 

 in Ihe vertical nests it always makes, is invariably left open) with a fine web 

 of whitish silk in which is rather proftisely intermingled minute bunches of 

 flossy silk of the same color — a barrier impenetrable to the sight. Within 

 this vertical cocoon, the transformation soon takes place ; so far as I have 

 seen, no thoracic girt whatever is constructed and the crotchets of the cre- 

 master are simply plunged into the silk at the bottom of the cocoon. 



Life history. The insect is single brooded, at least in the northern 

 half of its range, passing the winter sometimes as a mature caterpillar, 

 sometimes as a chrysalis. The first butterflies make their advent in the 

 latitude of Boston during the last week of May, usually about the 27th, 

 but sometimes by the 22nd, in the White Mountains during the first week 

 of June ; in southern New England it appears nearly a week earlier than 

 about Boston, the female, even, being sometimes taken as early as the mid- 

 dle of the month. In the early part of June it is exceedingly abundant, 

 and the dark females usually appear about this time, although they may be 

 occasionally seen as early as the normal type ; by the middle of June 

 most individuals captured at large about Boston will have abraded wings, 

 and during the latter half of the month the insects diminish rapidly, some- 

 times disappearing entirely by the 25th, though they often remain on the 

 wing until the end of the first week of July, or a trifle later. 



In the northern parts of New England and in Canada it may usually be 

 found even later than this ; while on the other hand Abbot records the cap- 

 ture of a specimen in Georgia as early as April 26 ; whether this indicates 



