Aug. 21, 1916 Life-History Studies of Cirphis Unipuncta 



811 



intervals by narrow white dashes, these the remnants of the white median line of 

 previous instars; laterad to this median stripe is a pale line which becomes inter- 

 fused with the former along its border; below is an interrupted dark-brown stripe 

 followed by a white stripe, and this by a rather conspicuous dark-brown stripe of the 

 same width as last and just above line of spiracles. Below the line of spiracles is a 

 conspicuous yellowish or cream-colored stripe with a more or less pinkish tint, con- 

 trasting with the dark-brown line above and the dusky-brown area beneath. Ven- 

 tral surface of body uniformly pale, but slightly brownish or dusky, the dorsum 

 appearing mottled and the pinkish shades rather conspicuous. Body sparsely cov- 

 ered with very fine hairs placed on minute black tubercles. Spiracles as in pre- 

 ceding instar. Legs pale dusky at joints and at tips. Pseudolegs pale and when 

 extended a conspicuous black band is visible on outer side and extending halfway 

 round the legs at their base. 



Measurements, average of two individuals, shortly after fifth molt: Length of body 

 24 mm., width of prothoracic segment 3.41 mm., of head 3.48 mm. Full grown: 

 Length of body 35 mm., width of pro thorax 3.8 mm., of widest abdominal segment 

 6.0 mm., of anal segment 3.5 mm., of head 3.4 mm. 



Individual 75, which had an extra instar — that is, seven — agreed in general mark- 

 ings with the description for the fifth-instar larva given above. Measurements for 

 this individual just before sixth molt as follows: Length of body 21.2 mm., width of 

 prothoracic segment 2.9 mm., of widest abdominal segment 4.0 mm., of proanal 

 segment 2.4 mm., of head 2.4 mm. 



The head widths are apparently good and substantial characters for distinguishing 

 larvae of different instars, the width varying only slightly in different individuals 

 and never varying in any instar for the same individual. In Table III are given 

 the average head widths for each instar, the records here given showing only those 

 measurements actually recorded in descriptive notes, although many other corrobo- 

 rative measurements were made at frequent intervals. 



Table III. — Width of head (in millimeters) of Cirphis unipuncta at different stages of 



growth 



