450 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



is a gradual tapering toward the posterior end. The external mouth 

 parts consist of a pair of sharp pointed chitinous hooks which are 

 used for piercing the egg shell or the body wall of the scales. 



The pupa is almost jet black in color, having changed very quickly 

 from that of the white larva. The length of the pupa varies from 1.5 

 to 3 mm. The large scutellum extends to the posterior margin of 

 the second abdominal segment. The duration of the pupal stage is 

 from 16 to 19 days. The most usual number under a single scale is 

 one, but not infrequently two are found, more rarely three, and in but 

 one case out of several thousand scales lifted, four pupae were found 

 in four separate cells beneath a single scale. 



The adults upon transforming from the pupa eat out a round hole 

 usually on the dorsal surface of the scale. They may remain a short 

 time beneath the scale before emerging, since occasionally upon lift- 

 ing a scale the mature insect will be seen to escape. They have been 

 observed to oviposit within 24 hours after emerging. The ovipositor 

 is inserted almost invariably under the arch at the posterior tip. 

 Sometimes two or three insertions are made and the egg deposited, 

 all within about half a minute. Oviposition has been observed to 

 occur under scales from which all the eggs had hatched, under scales 

 already occupied by Scutellista larva, under scales where not enough 

 eggs remained to bring the larva to maturity, and where the young 

 had hatched but died before emerging. In the field oviposition has 

 been noted where the scales had not yet reached the egg laying stage, 

 the so-called "rubber stage," and in the laboratory under forced con- 

 ditions it has occurred on scales after the first molt. Oviposition has 

 not been observed, even under laboratory conditions, in the case of 

 very young scales. Several eggs may be laid in succession but these 

 under different scales. Other individuals will lay eggs under these 

 same scales and this probably accounts for two or more larvae under 

 the same scale. 



Mr. E. W. Rust of this laboratory has apparently determined that 

 this insect may reproduce parthenogenetically. Mature black scales 

 with eggs were allowed to remain for a week under cover in order to 

 allow any chance for Scutellista eggs that might be present to hatch. 

 In the meantime several pupae were put each in a separate box and 

 the adults allowed to mature. Two of these unfertilized females were 

 placed in a vial containing a twig with a single black scale. Several 

 days later the scale was lifted and two Scutellista eggs and four newly 

 hatched larvae were found. Since the eggs hatch in from 4 to 6 days, 

 the eggs and larvae present must have come from the Scutellista liber- 

 ated. Parthenogenetic reproduction is not necessarily common for 

 the number of the sexes is approximately equal, and often even a 

 slight excess in favor of the males. 



