44 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



have been made bv the various authors. For northern latitudes Ave 

 are unable at present to form any definite conception as to the number 

 of generations. 



LENGTH OF THE LIFE CYCLE. 



The length of the life cycle or developmental period of a genera- 

 tion of the lesser peach borer, based on field observations, has already 

 been given in connection with Table II. The life cycle of the summer 

 generation was approximately 4i months, and of the winter genera- 

 tion T7 months. Fortunately Mr. Quaintance has succeeded in actu- 

 ally rearing a single specimen of this insect through its entire cycle, 

 in the grounds of the Insectary of this Bureau. On September 5, 

 1905, he placed 8 recently hatched larvae in small artificial wounds 

 made' 3 feet from the ground on the trunk of a peach tree. Each 

 larva was placed in a separate wound and the whole then protected 

 by a wrapping of paper. By October 1, not quite a month later, 5 

 of the larva? were found in their respective wounds and had grown 

 remarkably, being from a half to five-eighths of an inch in length 

 (13 to 16 mm.). On the 24th of the same month, or just over a 

 month and a half after hatching, the five larvee were still alive and 

 were either about to molt or had just done so; three of them measured 

 13 mm., one 16 mm., and the fifth, 19 mm., averaging about 15 mm. 

 The following spring, on April 5, 1906, another examination was 

 made, and it was found that 4 of the larva' had perished. The re- 

 maining one was inactive, but began to feed voraciously five days 

 later, and by about April 13 had formed its cocoon and pupated. 

 The moth, a male, emerged on May 14, 1906. 



The lengths of the respective stages for this individual were as fol- 

 lows : Egg, 7^ days ; combined larval instars, 220 days ; pupal instar, 

 31 days; making a total of 258 days, or 8.6 months for the cycle 

 (from August 28, 1905, to May 14, 1906). This agrees remarkably 

 Avell Avith time approximated for the Avinter generation in the South, 

 Avhere the periods of larval inactivity during the cold months are 

 naturally shorter, and hence growth is more rapid. The individual 

 reared Avas a descendant of ])arents from Fort Valley. Ga., mailed to 

 Washington. 



NATURAL ENEMIES. 



The lesser peach boier has a number of natural enemies, nearly all 

 of Avhich are parasites belonging to the order HymenoiJtera. 



Elachertiis n. sp., of the family Eulophida^ as determined by Mr. 

 E. S. G. Titus, is probably the most connnon, and is an internal para- 

 site Avhich is fatal to the host just before pupation. After the host 

 larva has constructed its cocoon the parasitic grubs eat their Avay 

 through its Ixxly and pupate nakedly in the host cocoon, entirely 

 filling it. As many as 138 of these parasites have been reared from 



