Key to Matsucoccus species from the eastern U.S. based on adult females

1. Venter with two sizes of setae; setae anterior of hind coxae and in medial areas of abdomen noticeably longer than other ventral setae......................................................... 2

— Venter with one size of ventral setae; setae anterior of hind coxae approximately same length as other ventral setae.............................................. M. alabamae Morrison (Fig. 6)

2(1). Cicatrices present on metathorax or abdominal segment I..................................... 4

— Cicatrices absent from metathorax and abdominal segment I.................................. 3

3(2). Cicatrices present in four rows on abdominal segments III–VI; cicatrices greater than 15 µm in diameter; with less than 100 cicatrices................................... M. macrocicatrices Richards

— Cicatrices present in five rows on abdominal segments II–VI; cicatrices less than 15 µm in diameter; with more than 100 cicatrices....................................... M. matsumurae (Kuwana)

4(2). With 20–32 multilocular pores; with 170–378 cicatrices; cicatrices in medial and mediolateral areas, but not in lateral areas......................................... M. gallicolus Morrison (Fig. 10)

— With 36–72 multilocular pores; with 437–900 cicatrices; cicatrices in medial, mediolateral, and lateral areas on some segments................ M. krystalae Ahmed and Miller, new species (Fig. 12)