December, ’23] 
armitage: present status of aphycus 
513 
in the “uneven-hatch” areas to a point where it cannot alone control 
the black scale. It is, however, logical to assume that this secondary 
parasitism will result in the usual cycle, with recurring periods of 
efficiency on the part of the Aphycus followed by periods of ascendency 
on the part of the secondaries. 
Up to the present time eleven hyperparasites have been taken as¬ 
sociated with Aphycus. Eight of these have been demonstrated ex¬ 
perimentally in the laboratory to attack the Aphycus, the other three 
being under suspicion. Those already demonstrated include in the 
order of their importance, Quaylea whittieri Gir.; a species of Eusemion, 
undescribed; Tetrastichus blepyri .Ash.; three species of Cheiloneurus; 
Eupelmus inyoensis .Ash., determined by Gahan; and Tltysanus niger 
Ash. The three under suspicion include one Cheiloneurus, one Eupel- 
mine and a Perissopterus determined by Gahan as mexicanus How. 1 
Quaylea whittieri Gir. is by far the most important hyperparasite 
attacking the Aphycus, in California outnumbering by far all of the 
others combined. Recovered rarely on Scutellista previous to the intro¬ 
duction of Aphycus louusburyi, it sprang into prominence immediately 
the latter became abundant in the field. The Quaylea became so 
abundant in some districts that at certain seasons of the year they were 
noted swarming by the hundreds around the tops of the trees on the ends 
of the new growth. In one case, from fifty selected scale parasitized 
by Aphycus, two hundred and thirty-three specimens of Quaylea were 
dissected and only five Aphycus were found to have escaped attack. 
In innumerable instances the Quaylea demonstrated their ability to 
parasitize all of the Aphycus, from two to seventeen, within a single scale. 
An undescribed species of Eusemion is second in importance as a 
parasite of the Aphycus. While occurring throughout Southern Cali¬ 
fornia to a greater or less degree it has been particularly abundant in 
Ventura and Los Angeles counties. Tetrastichus blepyri Ash. has also 
been rather abundant in the two counties mentioned. The other 
secondaries mentioned have been taken only in limited numbers. 
It is worthy of note that the secondaries are most abundant in those 
areas in which the distribution of the Aphycus was most actively carried 
on, because of the rapidly increased amount of host material available 
for their attack. In those areas, this season has seen practically every 
acre treated mechanically by either fumigation or spraying. The 
Aphycus, however, has not died out in these districts; it is very much 
T am indebted to Mr. Harold Compere, Assistant Entomologist, Beneficial 
Insect Investigations, University of California, for the above determinations. Mr. 
Compere is preparing for publication a paper covering these hyperparasites in detail. 
