Utah State University Extension
Black grass bugs are common insects in native and introduced range grasses. These insects belong to a large and diverse family of true bugs (Hemiptera: Miridae). Many species of black grass bugs occur in the United States, including 23 Irbisia spp. and 8 Labops spp. The most common species in Utah include I. pacifica and L. hesperius. Both types of black grass bugs can have adults with fully formed wings, but shortwinged forms are also naturally occurring.
Hodgson, Erin W., "Black Grass Bugs" (2008). All Current Publications. Paper 862.