INSECTS AFFECTING FOKESF TREES. 503 



Parasites. Mr. Scudder records the breeding of three hymenopterous parasites 

 from this insect, one a species of Bracon, another a minute Pcrilainpiis, both of these 

 rjr. Scudder states to be undescribed. He adds that the latter is by far the more 

 important. 



PITCH PINE RETINIA. 



Rctiiiia rigidana Fern. 



A form closely allied to the preceding also infests the pitch pine and works in a 

 similar manner. The larva is brownish and slightly larger than the preceding, and 

 the mot;h is stated to possess characters intermediate between those of R. frtistrana 

 Scudd. and R. coiiistockiana Fern. 



PITCH TWIG MOTH. 



Retinia coiiistockiana Fern. 



The pitch masses of this insect may frequently be met with on the upper side of 

 smaller limbs and twigs on hard pines, and fresh masses of pitch laying upon an 

 older accumulation is nearly conclusive evidence that the larva is still at work, and 

 on cutting open such a mass, it will be seen to cover the entrance of a small 

 gallery which runs longitudinally and which may extend a distance of i to 2 or 

 more inches, sometimes in one and in other cases in both directions, plate 12, 

 figure I. 



This species was very abundant on the hard pines at Karner in 1901. The life 

 history of the insect may be summarized as follows: The winter is passed in the 

 larval or caterpillar stage, the operations in the spring beginning about the 15th of 

 April. The spring addition is frequently nearly equal to the original size of the 

 pitch mass and the demarcation between the old and the new is very evident. 

 Empty pupal cases were observed in the field June 12th, though no adults were 

 btaincd in breeding cages till the 20th. Prof. Comstock expresses the opinion that 

 this insect passes through two generations in a season, but our own observations 

 hardly bear out tliis conclusion. 



Description. The moth is a delicate, grayish-brown, yellow insect, having a 

 wing spread of about ■'.( of an inch, plate 12, figure 21. The pupa is brownish, 

 about jX of an inch in length, and tlie abdominal segments are each provided with 

 two transverse rows of stout teeth. These prove of great assistance to the pupa 

 in wriggling out of its burrow. 



The larva is about V2 of an inch long when full grown, the head and thoracic 



o 



