18 



BULLETIN 838, U. S. DEPARTMENT OF AGRICULTURE. 



Fig. 4. — Nipus Mplagiatus, 

 a coccinellid enemy of the 

 cypress bark scale. X 25. 



PREDACIOUS AND PARASITIC ENEMIES. 



There are several coecinellids which aid in the control of the 

 cypress bark scale. None of them is aggressive enough, however, 

 to affect its abundance very materially. 



A very small ladybird, Nipus Mplagiatus Casey (fig. 4), is the 

 most abundant and widespread enemy of the scale. This is a sturdy 

 little beetle, about 1.3 mm. in length, brown- 

 ish black, with a lighter amber spot in the 

 center of each elytron. It is generally present 

 wherever the scale insect is to be found. On 

 one side of a cypress limb in a space 3| by 24 

 inches (84 square inches), there were found 

 46 specimens of this coccinellid and in certain 

 parts of this area there were as many as four 

 beetles to the square inch. There were un- 

 doubtedly still more out of sight under the 

 bark scales. Yery few of the larva? of this 

 beetle were seen but this may be accounted for 

 by their extremely small size and their pale 

 brown color. 

 A small black nitidulid beetle, Cybocephalus californicus Horn 

 (fig. 5), is very abundant and is sometimes confused with the above 

 coccinellid. It is, however, slightly smaller, shiny black, with more 

 delicate legs, and of a more compact globose form. This beetle has 

 not been seen actually feeding upon the scale insect, yet it is believed 

 to be an aggressive predacious enenry. It is 

 always found about the scale insect, and often 

 with its head in the bark crevices as if feeding 

 upon the scale insect. The larva of this 

 beetle is small and white and not easily found. 

 The twice-stabbed ladybird, Chilocorus bi- 

 vulnerus Muls., is an abundant and aggres- 

 sive predator upon the cypress bark scale. 

 This beetle is often found upon cypress, feed- 

 ing upon this insect pest. 



The common black-spotted red ladybird, 

 Hippodamia convergent Guerin, has been 

 found a few times feeding upon the scale. As this beetle breeds in 

 great numbers in the Sierra Xevadas, it probably feeds upon the scale 

 on incense cedar in its native haunt. 



Larvae of the common brown lacewing, Sympherobius angustus 

 Banks, are often found feeding upon the cypress bark scale and 

 aiding materially in retarding its increase and spread. 



A few specimens of a small hymenopterous parasite have been 

 reared from caged material of this scale insect. It can not, however, 



Fig. 5. — Gyhoceplvalus cali- 

 fornicus, a nitidulid bee- 

 tle always found about the 

 cypress bark scale. X 25. 



