98 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES, 



than those of Scolytus ri/gulosus, the maximum length being about 

 2f inches, with an average of 2^^ inches. 



There are two complete broods each year — the summer brood and 

 the fall brood, the latter being the hibernating one, the beetles ap- 

 pearing in early spring. Beetl.es of the summer brood appear in 

 maximum numbers during the last half of August, as shown more 

 in detail in the following table : 



Table I. — Emergence of summer brood of beetles of Pltloootribits Jiminaris. 



"The first column shows beetles actually conntod and taken from a breedins caiie : the 

 second row of figures shows, somewhat estimatod, numbers of beetles gathered on screens 

 at windows. All counts made between 4 and 6 p. m. 



''This table shows August 21 to be the date of maximum emergence of beetles. 



DESCRIPTION. 



Averase length, 2.25 mm., average width, 0.75 mm. Body elongate, subcylin- 

 drical, strongly punctured and with yellowish bristles arising from the punc- 

 tures; color varying from light brown to almost black. Head globular, nearly 

 vertical in front, anterior part fringed ; eyes narrowly oblong, closely joined to 

 the scape and extending about half their length below it: mandibles short and 

 broad, distal part curved and strongly acute; mouth parts partly inclosed, gular 

 suture distinct ; funiculus of antennte five-jointed ; club compressed, composed 

 of 3 triangular segments; first joint longer than wide, globular; scape circular, 

 clavate. Thorax almost cylindrical, strongly angled at caudal end. First and 

 second coxa^ widely sei)arated, globular ; femur stout, outer edge serrated ; tibia 

 stout, compressed, lower half of outer edge serrated and ending in an apical 

 tooth; tarsus stout, shorter than tibia, third joint bilobed, fourth indistinct, 

 fifth as long as first and second together; tarsal claws simple. Ventral side of 

 abdomen and i)osterior edge of last segment strongly concave; elytra anteriorly 

 rounded and deeply margined, sides parallel, surface with regular striiie which 

 contain circular, regularly placed depressions, elevated parts with yellowish 

 bristles arising from faint punctures. 



