59 



EVENING SESSION, FRIDAY, AUGUST 19, 1898. 



The first paper of the evening was presented by Mr. A. F. Burgess, 

 as follows : 



AN ABNORMAL COCCINELLID. 



By A. F. Burgess, Maiden, Mass. 



The economic importance of scale insects and Aphids is correlated 

 with that of the Coccinellids, a group which furnishes the chief checks 

 upon their increase. The introduction of the Vedalia cardinalis and 

 allied species into California will illustrate the benefit derived from an 

 accurate knowledge of the habits of these predaceous beetles, and a 

 thorough study of the food habits of our native ladybirds probably would 

 show that they are the chief agencies controlling the increase of many 

 of our indigenous scale insects, and without their assistance these 

 insects might prove highly injurious. 



Our most common Coccinellid, Adalia bipunctata, plays an important 

 part in checking the undesirable increase of certain Coccids and Aphids 

 in this region, and an interesting fact concerning this species, noted 

 during the present season, may be recorded properly at this time. On 

 April 13 while collecting in the Middlesex Fells, Maiden, Mass., I took 

 a pair of ladybirds in coitu on a white birch upon which Aphid eggs 

 were thickly massed. An examination of the specimens showed the 

 female to be a normal Adalia bipunctata, while the male was black in 

 color with a blood-red marking at the humeral angle of each elytron; 

 posterior to each of these markings was a small dot of the same color. 

 The beetles were fed upon Aphid eggs at the insectary, and upon April 

 20 the female laid a cluster of fourteen eggs, followed by another of 

 eight eggs on April 23. These lots of eggs hatched in four and seven 

 days, respectively. The larvae were fed upon Aphids, and from the 

 material left after the preservation of specimens two imagos were 

 reared, both being of the black form. The male parent insect was 

 placed with a female Chilocorus bivulnerus on May 3, but, as expected, 

 died without mating. The female Adalia continued to lay up to June 1, 

 the eggs, with the exception of the last four clusters, proving fertile. 

 Many of the larvae died before completing their transformations, and 

 only a single black adult was reared. 



On May 5 another pair of these insects were found in coitu near the 

 place where the first pair was taken, and in this case the male was of 

 the black type, the female being a normal Adalia. From eggs depos- 

 ited by this female there were reared two beetles of the black form and 

 an Adalia of the normal color and form. These three insects were 

 placed in a jar with the three beetles from the brood previously men- 

 tioned. On June 15 two of the black form were found pairing, the eggs 

 subsequently laid proved fertile, but the larvae died before reaching 

 maturity. June 26 an Adalia male and a black female (both belonging 



